Between 1991 and 1996, Al Qaeda took part in several major terror attacks. Al Qaeda was involved in the bombing of two hotels in Aden, Yemen, which targeted American troops en route to Somalia on a humanitarian and peacekeeping mission . It also gave massive assistance to Somali militias, whose efforts brought the eventual withdrawal of U.S. forces in 1994. Bin Laden was also involved in an assassination attempt against Egyptian president Hosni Mubarak in Ethiopia in June 1995. Two major terrorist actions against the U.S. military in Saudi Arabia, a November 1995 attack in Riyadh and the June 1996 Khobar Towers bombing, also fit Al Qaeda’s strategy at the time, but their connection to Al Qaeda is not entirely clear. There is little evidence to suggest a significant connection between bin Laden and the first World Trade Center bombing in 1993.
After moving to Afghanistan, bin Laden escalated his anti-American rhetoric. In an interview with the Independent in July 1996, bin Laden praised the Riyadh and Dhahram attacks on U.S. forces in Saudi Arabia, saying it marked “the beginning of war between Muslims and the United States.†He did not take responsibility for the attacks, but said that “not long ago, I gave advice to the Americans to withdraw their troops from Saudi Arabia.†On August 23, 1996, bin Laden issued Al Qaeda’s first “declaration of war†against America, his “Message from Osama bin Laden to his Muslim brothers in the whole world and especially in the Arabian Peninsula: declaration of jihad against the Americans occupying the Land of the Two Holy Mosques (Saudi Arabia); expel the heretics from the Arabian Peninsula.â€
Subsequently, Al Qaeda escalated its war against the U.S. In August 1998, Al Qaeda bombed two U.S. embassies in East Africa (Nairobi, Kenya, and Dar es Salaam, Tanzania) killing more than 200 people, including 12 Americans. In retaliation, the U.S. attacked targets in Sudan and Afghanistan. In October 2000, Al Qaeda bombed the U.S.S. Cole, an American guided-missile destroyer at Aden, Yemen, killing 17 American servicemen. It committed its most devastating attack on September 11, 2001, when 19 Al Qaeda operatives hijacked four passenger planes and drove two into the Twin Towers in New York City and one into the Pentagon; a fourth plane crashed in rural Pennsylvania. Nearly 3,000 people were killed in the attack.