Federal prosecutors accused Osama bin Laden's militant Islamic organization Friday of bombing the U.S. Embassy in Kenya, offering the most detailed description to date of an alleged terrorist conspiracy to kill Americans in East Africa.

A criminal complaint was filed against Mohammed Saddiq Odeh, a bin Laden disciple who was arraigned in Manhattan on charges that he helped plan the bombings. Prosecutors suggested about as strongly as they could without a formal indictment that bin Laden was responsible for the attack. The complaint repeatedly blamed the bombing on al Qaida, an organization at the heart of bin Laden's farflung terrorist network, and provided a detailed history of bin Laden's anti-American sentiments.However, the complaint did not offer any direct evidence tying bin Laden to the bombing in Kenya on Aug. 7 or to a nearly simultaneous blast at the U.S. Embassy in Tanzania, although it did state that most members of bin Laden's group were told to leave Kenya by Aug. 6. The two explosions killed 263 people, including 12 Americans, and injured more than 5,000 others.

"This is an important step forward, but we are not letting up," said Attorney General Janet Reno.

Odeh, who allegedly told Pakistani authorities that he helped plan the Nairobi attack, was flown into New York from Nairobi Friday. He was charged with 12 counts of murder, one count of murder conspiracy and one count of conspiracy to use weapons of mass destruction.

It also said two witnesses told the FBI that within the last year Odeh had visited Dar es Salaam, the site of the blast in Tanzania, but Odeh was not charged in connection with that attack.

Mohamed Rashed Daoud Al-'Owhali is another bin Laden associate who allegedly told the FBI he threw a grenade at a guard while riding the bomb-laden truck that devastated Nairobi. He was arraigned Thursday on similar charges.