New York: US Federal prosecutors in Manhattan on Friday dropped terrorism charges against slain al Qaeda chief Osama bin Laden who was killed by American commandos in Pakistan.

The fist indictment was filed against bin Laden in Federal District Court in Manhattan in 1998 and charged him with conspiracy to attack United States defense installations.

The indictment grew after the 9/11 attack, which was masterminded by bin Laden.

On Friday, US District Judge Lewis Kaplan signed an order approving government's request to drop charges.

ABC News reported that on Thursday, Assistant US Attorney Nicholas Lewin presented a formal recommendation to US. Attorney Preet Bharara that Bin Laden not be prosecuted on
any of the charges, given that he is dead.

"On or about May 1, 2011, while this case was still pending, defendant Usama Bin Laden was killed in Abbottabad, Pakistan, in the course of an operation conducted by the United States," Lewin noted.

He further added that "al Qaeda has itself publicly acknowledged the death of bin Laden."

Among other pronouncements, a recently released video depicts senior al Qaeda leader and co-defendant Ayman al Zawahiri acknowledging bin Laden's death.

The case again bin Laden has now been officially closed.

Osama was indicted in June 1998 in federal court in Manhattan on charges he supported the ambush that left 18 US soldiers dead in Somalia in 1993.

The indictment was later revised to charge the slain al-Qaeda chief in the dual bombings of two American embassies in East Africa that killed 224 on August 7, 1998, and in the
suicide attack on the USS Cole in 2000. None of the charges involved the September 11, 2001, terrorist attacks.