Bojinka

As soon as Yousef arrived in Manila along with other so-called "Arab Afghans" that were making cells in Manila, he started to work on making bombs. Yousef had shown up in Singapore with Khan earlier in fall 1994. The two got their Philippine visas in Singapore.

His first operational test of his bomb was inside a mall in Cebu City. The bomb detonated several hours after Yousef put it in a generator room. It caused minor damage, but it proved to Yousef that his bomb was workable.

He left Manila for several days, but was met by Islamist emissaries upon his return to Metro Manila. They asked him to attack United States President Bill Clinton, who was due to arrive in the Philippines on November 12, 1994 as part of a five-day tour of Asia. Yousef thought of several ways to kill the president, including placing a bomb on Clinton's motorcade route, firing a Stinger missile at Air Force One or the presidential limousine, and killing him with phosgene, a chemical weapon. He abandoned the idea, as it would be too difficult to kill the President. However, he incorporated his plan to kill the Pope into the Bojinka plot.

In 1994, Yousef and Khalid Sheik