The United States filed charges of conspiracy and providing support for terrorism on Thursday against a Guantanamo detainee accused of working for Osama bin Laden and whose lawyers last year successfully challenged the military tribunal system before the US Supreme Court.
Salim Ahmed Hamdan is the third Guantanamo detainee charged under a new set of rules for military trials signed last year by US President George W Bush after the Supreme Court rejected the previous system.
Hamdan, who is from Yemen, has been detained at Guantanamo since May 2002. His legal challenge forced the Bush administration and Congress to draft new rules for the military trials, known as commissions, for the men held at the US military prison at Guantanamo Bay in southeastern Cuba.
He is expected to be arraigned in early June, when he can enter a plea to the charges.
In the charging documents, the military says Hamdan conspired with bin Laden and other al-Qaida leaders in the bombings of the US Embassies in Kenya and Tanzania in 1998, the 2000 attack on the USS Cole and the Sept 11, 2001, terrorist attacks in the United States.
In addition to working as bin Laden's driver and bodyguard, the US says Hamdan transported and delivered weapons to al-Qaida and its associates and trained at terrorist camps. He could get life in prison if convicted of either charge.
Hamdan's lawyer, Navy Lt Cmdr Charles Swift, says the Yemeni admits working as a driver for bin Laden - being one of about eight men with similar duties - but denies any significant role in attacks against the United States.
A Pentagon spokesman, Navy Cmdr Jeffrey Gordon, disputed the assertion that Hamdan was just a low-level player. Hamdan's lawyers are seeking to have the case dismissed on the grounds that minor figures like him cannot be charged with conspiracy under the Law of War and that providing material support to terrorism was not a war crime until the US made it one in last year's Military Commissions Act.
"The government has decided to charge him with a series of ex-post-facto crimes," Swift said. "You can't write the law after the fact."
His lawyers hope the courts will step in to halt the trial. The new rules require the government to start the trial within 120 days of arraignment.
Hamdan is expected to be arraigned the same week as Canadian detainee Omar Khadr, who is charged with murder, attempted murder, providing support to terrorism, conspiracy and spying. Charged under the new trial rules, Australian David Hicks pleaded guilty to supporting terrorism in March and was sentenced to nine months in prison. He will serve the sentence in his native country as part of an agreement with the court.
The US says it plans to file charges against about 80 detainees at Guantanamo, where it now holds about 380 men on suspicion of links to al-Qaida, the Taliban or associated groups.