Al-Qaida, "The Base." Also known as Maktab al-Khidamat, International Islamic Front for Jihad Against the Jews and Crusaders; Group for the Preservation of the Holy Sites; Islamic Army for the Liberation of the Holy Places; Islamic Army for the Liberation of Holy Shrines; and Islamic Sal.

The group is sometimes referred to as Al-Qaida Central, separating the core from regional and country-based branches.

The Al-Qaida terrorist network, headed by Osama bin Laden, has worldwide reach. Many of its leaders resided in Afghanistan prior to the U.S. military actions against the Taliban regime in 2001. After that invasion, the Al-Qaida leadership fled Afghanistan into the mountainous tribal territories of western Pakistan. The lawless frontier region has apparently served as a safe haven for Al-Qaida and Taliban militants since that time.

Following the onset of Operation Iraqi Freedom, foreign terrorist groups entered Iraq and took part in attacks against coalition forces. Some of these terrorists were said to be Al-Qaida members. In December 2003, U.S. troops found a large cache of weapons in Samarra, Iraq, that also included Al-Qaida videotapes and literature. In 2004, Al-Qaida in Iraq was founded and aligned itself with Osama bin Laden. Other Al-Qaida branches operate largely independently in various parts of the world (see separate records for more information).

Al-Qaida's goal is to work with other Islamic extremist groups to overthrow regimes it deems "non-Islamic" and to establish a global Islamic religious government, or caliphate. Al-Qaida also seeks to expel Westerners and non-Muslims from Muslim countries.

Actual numbers of Al-Qaida members are unknown. The network does not rely on a large membership to have its widespread impact, but works through other groups by providing training and other operational support. Intelligence experts estimate that perhaps 200 people belong to the core Al-Qaida group, many of whom receive regular salaries.

Thousands of Al-Qaida members have been killed or captured in the international anti-terrorist campaign that began after the Sept. 11, 2001, terrorist attacks against the U.S., according to various official and unofficial estimates. Despite those counter-terrorist successes, Al-Qaida is believed to have largely reconstituted itself in the Afghan-Pakistan border region.

Al-Qaida leader Osama bin Laden is the son of Mohammad bin Awdah bin Laden of southern Yemen. Bin Laden's father became a very wealthy construction magnate after being hired to renovate the holy cities of Mecca and Medina. Bin Laden was reportedly worth an estimated $300 million, although the U.S. is believed to have frozen a substantial portion of this money. He has used some of his inheritance to fund Al-Qaida operations and training programs.

Al-Qaida also maintains a fundraising network through several front organizations. It solicits donations and launders money donated to legitimate Muslim organizations. The U.S. and its partners in the international anti-terrorist coalition have attempted to shut down Al-Qaida's fundraising efforts.

Al-Qaida and Egyptian Islamic Jihad united in 2001; the two groups share resources and links to other groups.

Al-Qaida also serves as an umbrella organization for the worldwide network known as the International Islamic Front for Jihad Against the Jews and Crusaders. This terrorist confederation includes many Sunni Islamic extremist groups such as Egyptian Islamic Jihad, al-Gamaat al-Islamiyya, Islamic Movement of Uzbekistan, Jemaah Islamiyah and Harakat ul-Mujahidin.

During the 1980s, resistance fighters in Afghanistan developed a worldwide support network to recruit Arabs to fight Soviet occupation forces. This network, known as the Maktab al-Khidamat, helped finance, train and recruit mujahideen fighters throughout the world.

After the 1989 Soviet withdrawal from Afghanistan, the network of mujahideen supporters came under the control of Osama bin Laden.

Bin Laden began primarily as a supporter and fundraiser for the mujahideen. As he expressed more radical Wahhabi Islamic beliefs, bin Laden gathered his own network of militant supporters. He then spread his influence to other groups, expanding the global reach of the Al-Qaida network.

Al-Qaida has developed into a radical Islamic group dedicated to the overthrow of what it sees as corrupt and heretical governments of Muslim countries. Al-Qaida in particular views the Saudi regime as corrupt and not committed to true Wahhabi values.

The group has an anti-Western animus. Al-Qaida considers the U.S. the main enemy of Islam. In particular, it has sought the expulsion of all U.S. military forces from Saudi Arabia, the home of the two holiest Sunni shrines, Mecca and Medina.

Al-Qaida suffered a significant setback when its ally, the Taliban government in Afghanistan, was overthrown by U.S. and coalition forces. Al-Qaida leaders retreated to the frontier areas of Pakistan, where they have been sheltered by sympathetic tribes. U.S. Intelligence officials believe that Al-Qaida has been able to reconstitute itself, open multiple training camps and re-establish some technical capacities.

Many Al-Qaida leaders were captured or killed in the years following the Sept. 11, 2001, terrorist attacks in the U.S. However, Al-Qaida is believed to have established a new group of leaders to replace them. The new leadership is thought to be more dispersed, with autonomous planning centers, a change from the more hierarchical structure prior to the 2001 attacks.

As of early 2009, Al-Qaida remained the major threat to U.S. national security in the view of top officials, including the head of the Central Intelligence Agency. In an April 2008 review of the status of Al-Qaida, the U.S. State Dept. noted that the group had leveraged its influence through an international network of terrorist organizations. The group has reconstituted some of its pre-9/11 operational capabilities through the exploitation of Pakistan's Federally Administered Tribal Areas (FATA), the replacement of captured or killed operational lieutenants and the restoration of some central control by its top leadership, in particular Ayman al-Zawahiri, according to the assessment.

The State Dept. noted in 2007 that Al Qaida has continued to build affiliations with regional insurgent groups, notably the Algerian Salafist Group for Preaching and Combat, which renamed itself Al-Qaida in the Islamic Maghreb (AQIM). AQIM is largely focused on Algeria and has been behind spate of attacks. On Dec. 11, 2007, it attacked U.N. offices in Algeria, apparently indicating that the group considers foreign facilities as active targets. In February 2008, the director of National Intelligence expressed concerns about Al-Qaida's ability to use the FATA region in Pakistan as a sanctuary and base of operations.

To counter Al-Qaida, the U.S. has intensified its use of unmanned Predator drones. The drones have been used to launch missiles against high value targets, including Al-Qaida operatives, in the FATA region. In early 2009, military sources disclosed that the attacks were having a significant effect in diminishing Al-Qaida's operations.

Aug. 7: There were 254 people killed and over 5,000 injured when a car bomb exploded outside the U.S. Embassy in Nairobi, Kenya. A five-story building was toppled in the explosion.

A car bomb exploded outside the U.S. Embassy in Dar es Salaam, Tanzania, on the same day, killing 10 and injuring 77. Al-Qaida was blamed for both attacks.

Sept 11: More than 3,000 people were killed when terrorists hijacked four U.S. passenger planes and flew them into the World Trade Center and the Pentagon. One of the planes crashed in Pennsylvania. Al-Qaida took responsibility for the attacks.

October: U.S.-led forces launched an offensive against the Taliban regime in Afghanistan after it refused to surrender Osama bin Laden.

Dec. 12: Zacarias Moussaoui, who had been detained on immigration charges the previous August, was charged in connection with the Sept. 11 attacks.

Dec. 23: Richard Reid, a Briton converted to Islam, was overpowered by flight attendants on a flight from Paris to Miami as he attempted to ignite a shoe bomb. He was believed to be an Al-Qaida operative.

May 17: At least five people were killed and 40 wounded in Islamabad, Pakistan, when terrorists threw grenades into a local church. The assailants were thought to be members of Al-Qaida.

April 11: An alleged Al-Qaida member drove a truck filled with natural gas into a wall of a Tunisian synagogue, killing 19 and injuring 15.

June 14: A car bomb outside the U.S. consulate in Karachi, Pakistan, killed at least 11 people and injured more than 40. Al-Qaida was blamed for the attack.

Aug. 28: German officials charged Mounir al-Motassadek, a 28-year-old Moroccan citizen living in Germany, with crimes related to the attacks on Sept. 11, 2001.

Sept. 11: Ramzi Binalshibh was arrested in Pakistan and accused of being a leading planner of the attacks in New York and Washington.

Oct. 12: A series of simultaneous bombings at nightclubs in Bali, Indonesia, killed nearly 200 people and injured more than 250. Jemaah Islamiayh, which reportedly has connections to Al-Qaida, was believed to have been behind the attacks.

Nov. 28: Two missiles were fired at an Israeli passenger jet near Mombasa, Kenya. In addition, 13 people were killed and 80 were injured when a bomb exploded in a Mombasa hotel that Israeli tourists were known to frequent. Al-Qaida is believed to have been responsible for both attacks.

July 23: Iran admitted for the first time it had been holding senior Al-Qaida members.

Nov. 15: The Nov. 24 issue of the Weekly Standard detailed information obtained from a U.S. Defense Dept. memo that cited apparent links between Al-Qaida and Iraq. According to intelligence reports from several U.S. agencies, Iraq and Al-Qaida maintained operational links from the early 1990s until the beginning of Operation Iraqi Freedom in March 2003. Much of the information was detailed and corroborated by several sources. Some of the information gleaned was said to be more than a decade old, but information was also reportedly obtained from recent interrogations of Al-Qaida members and former Iraqi officials.

Dec. 30: U.S. troops belonging to Task Force Ironhorse discovered a large cache of weapons in Samarra, Iraq, that also included Al-Qaida literature and videotapes.

Feb. 24: CIA Director George Tenet said the Al-Qaida network had been seriously damaged but continued to spread its radical anti-American agenda to other terrorist groups that then posed a greater threat to the U.S. "The steady growth of Osama bin Laden's anti-U.S. sentiment through the wider Sunni (Islamic) extremist movement, and the broad dissemination of Al-Qaida's destructive expertise, ensure that a serious threat will remain for the foreseeable future -- with or without Al-Qaida in the picture," testified Tenet before the Senate Intelligence Committee.

March 11: A series of terrorist bombings was carried out in several passenger trains in Madrid, killing nearly 200 people and injuring more than 1,800. The Islamic Combatant Group, a militant Moroccan group with links to Al-Qaida, was suspected of orchestrating the attacks.

April 15: In an audio recording, a man claiming to be Osama bin Laden offered the countries of Europe a truce if they would withdraw their forces from Muslim countries and halt attacks against Muslims.

Oct. 29: Al-Qaida released a videotape in which Osama bin Laden threatened fresh attacks on the U.S.

April 22: Al-Qaida suspect Zacarias Moussaoui, a French citizen of Moroccan descent, pleaded guilty in U.S. District Court in Virginia to conspiracy and a number of other charges relating to the Sept. 11, 2001, terrorist attacks in the U.S. Moussaoui was arrested prior to the attacks.

Aug. 4: Ayman al-Zawahiri, Al-Qaida's number two leader, issued a video-taped warning to the U.S. and Great Britain threatening more terrorist attacks. "There will be no salvation until you withdraw from our land, stop stealing our oil and resources, and end support for infidel [Arab] rulers," said Zawahiri to the international coalition in Iraq.

November: Pakistani authorities in Quetta captured Mustafa Setmarian Nasar, also known as Abu Musab al Surim. The U.S. had a $5 million bounty on Nasar's head

April 12: Muhsin Musa Matwalli Atwah, an Egyptian Al-Qaida operative indicted for involvement in the 1998 attacks on U.S. embassies in East Africa, was killed in North Waziristan by a Pakistani air strike.

July 28: In a video statement released during the conflict between Israel and Hezbollah, Zawahiri called on Muslims around the world to "rise up seeking martyrdom and attack the crusaders and Zionists." "The Al-Qaida organization will not stay silent regarding what the Muslims in Palestine and Lebanon are facing," Zawahiri said. "As they attack us everywhere, we will attack them everywhere. They gang up to wage war on us; our (Islamic) nation will fight them and wage war on them."

Sept. 11: On the anniversary of the 2001 attacks in the U.S., Zawahiri issued a new video-taped message calling on Muslims to step up their attacks, intimating that Israel and Gulf Arab states might be the next target. He also called on Muslims to fight U.S. allies in Somalia.

April: U.S. intelligence officials said Al-Qaida was establishing a new, more dispersed and autonomous group of leaders to replace those captured and killed since Sept. 11, 2001.

July 11: A British judge sentenced four men to life sentences for participating in the July 21, 2005, bomb plot in London. The botched attack designed to detonate explosives on three subway trains and a bus was a "viable... attempt at mass murder" and was "Al-Qaida-inspired and controlled," the judge said.

July-August: Pakistani government truces with tribal groups collapsed in North Waziristan in July and in South Waziristan in August. The cease-fires had been in place since September 2006. Pakistani military forces subsequently re-entered the tribal areas.

Sept. 7: A new Osama bin Laden video surfaced for the first time in three years. The tape was believed to have been produced after June because of a reference to French elections. Bin Laden urged ordinary Americans to unite against their capitalist system and convert to Islam.

Sept. 7-8: Militants killed 49 people in Algeria in two days. In one suicide attack, 19 people were killed as they were among a crowd waiting to see Algerian President Abdelaziz Bouteflika in Batna. In the second attack, 30 people died when a truck loaded with explosives drove into a military barracks in the port of Dellys. Al-Qaida in the Islamic Maghreb (AQIM) claimed responsibility for the attacks.

Dec. 12: AQIM claimed responsibility for exploding two car-bombs in Algiers. At least 40 people were killed in the attacks. The militants targeted the Algerian Supreme Court and the headquarters of the U.N.'s refugee agency.

Dec. 27: Former Pakistani Prime Minister Benazir Bhutto was assassinated at an election rally in Rawalpindi. After an attacker shot Bhutto, he blew himself up, killing at least 30 other people. The Italian news agency Adnkronos International later reported that an Al-Qaida leader, Mustafa Abu Al-Yazid, told the agency in a phone call that the group was responsible for the attack.

June 2: Six persons were killed and several others were injured during a car bomb attack on the Danish embassy in Pakistan. Al-Qaida's Mustafa Abu Al-Yazid claimed responsibility for the attack, which he said was conducted in retaliation to the publication of a cartoon in a Danish newspaper deemed offensive to Islam.

July 6: At a war-crimes trial conducted at the U.S. detention center at Guantanamo Bay, Cuba, a tribunal convicted a Yemini former driver for Osama Bin Laden for providing support for terrorist activities.

Aug. 20: A U.S. Predator unmanned aircraft killed and injured several Al-Qaida members in Pakistan's tribal area, including Haqqani network collaborators. Among the injured was Haji Yacoub, an Al-Qaida operative.

Sept. 17: Ten persons were killed during an attack on the U.S. Embassy in Yemen. A government official said the attack was conducted by Al-Qaida in retaliation for steps taken by the Yemeni government to combat terrorism. The attackers used vehicle bombs, rocket-propelled grenades and automatic weapons. Local guards and some civilians were killed in the assault but the militants failed to breach the U.S. compound. One American was killed. A U.S. official said the attack bore the characteristics of Al-Qaida assaults.

Feb. 3: Al-Qaida released an audio message condemning Israel and calling for renewed attacks. The message was issued by the group's second in command, Ayman al-Zawahiri, who

blamed "Western collaboration" in supporting Israel and blamed Israel's allies for not distinguishing "the killer from the victim" in Gaza. The message was a follow-up to a Jan. 2 communication which called the fighting between Israel and the Palestinians in Gaza a "massacre."

Feb. 9: An American account listed at least 13 Predator drone attacks conducted between December 2007 and September 2008 against high-value targets, including members of Al-Qaida, in the border areas of Afghanistan and Pakistan, according to a news report published in Pakistan.

March 3: The Saudi Embassy in Pakistan reported it had received a threat from Al-Qaida warning of attacks against Saudi Airlines and other installations in Pakistan. Saudi officials alerted the Pakistani Interior Ministry.