Wikipedia: Al-Qaida

Al-Qaida (also spelled al-Qaeda, al-Qa'ida, al-Quaida, Arabic for the base) is a guerrilla terrorist organisation established by Osama Bin Laden in the late 1980s to draw together Arabs who had gained combat experience in Afghanistan whilst fighting against the Soviet invasion. The organisation initially helped to finance, recruit and train Sunni Islamic extremists for the Afghan resistance. Al-Qaida is thought currently to have several thousand members. The ultimate goal of al-Qaida is to establish a Pan-Islamic Caliphate throughout the world by working with allied Islamic extremist groups to overthrow regimes it deems "non-Islamic" and expelling Westerners and non-Muslims from Muslim countries. Al Qaida's brand of Islamic intolerance has its roots in the Wahhabite sect, the creed embraced by the current rulers of Saudi Arabia. (See Islamism).

It issued a statement under banner of "the World Islamic Front for Jihad Against the Jews and Crusaders" in February 1998 saying that it was the duty of all Muslims to kill US citizens, either civilian or military, and their allies everywhere.

Al-Qaida plotted to carry out terrorist operations against US and Israeli tourists visiting Jordan for millennial celebrations, however the Jordanian authorities thwarted the planned attacks and put 28 suspects on trial. They conducted the bombings in August 1998 of the US Embassies in Nairobi, Kenya, and Dar es Salaam, Tanzania, killing more than 300 people and injuring more than 5,000 others.

They claim to have shot down US helicopters and killed US servicemen in Somalia in 1993, and also to have carried out three bombings which were targeted at US troops in Aden, Yemen, in December 1992. They are also thought to be responsible for the August 1998 U.S. embassy bombings and the October 2000 USS Cole bombing.

Al-Qaida has a worldwide reach, has cells in a number of countries, with strong ties to Sunni extremist networks. Bin Ladin and his lieutenants hide in Afghanistan. The group has a number of terrorist training camps there.