Five prisoners held at the US military prison at Guantanamo Bay, Cuba, have been charged with crimes including murder and will face military trials.
Nine prisoners at Guantanamo Bay have been charged with crimes
The charges bring to nine the number of Guantanamo detainees formally accused.
Earlier, the US Supreme Court said it would consider whether the military tribunals used to try Guantanamo suspects are constitutional.
The court will hear a challenge in 2006 brought by a Yemeni detainee who is a former driver for Osama Bin Laden.
The Supreme Court case was launched by lawyers for Salim Ahmed Hamdan, who has been held at Guantanamo since 2002.
The Yemeni man, one of the nine prisoners charged so far, is accused of conspiracy to commit war crimes, including terrorism. He denies the charges.
The latest detainees charged include two Saudi Arabians, an Ethiopian and a Canadian.
Toronto-born Omar Khadr, who was 15 when arrested, is charged with murder and attempted murder, for allegedly killing a US medic in Afghanistan with a grenade and planting mines targeting US convoys.
The other four are charged with conspiracy to commit murder, attacks on civilians and terrorism offences.
Hamdan says he was just a driver and not an al-Qaeda member
Barbara Olshansky, a lawyer for the New York-based Center for Constitutional Rights, condemned the announcement of new military trials on the same day that the US Supreme Court said it would review their legality.
The Supreme Court hearing for Mr Hamdan follows a ruling by a US appeals court in July that the trials for detainees at Guantanamo were lawful.
Mr Hamdan's trial had been halted the previous November, after the judge said it could not proceed until a decision had been made on whether he was a prisoner of war under the Geneva Conventions.
Mr Hamdan, who denies belonging to al-Qaeda, contested his status as "enemy combatant". His lawyers were seeking to force US authorities to try him in a civilian court, arguing that the military tribunals were illegal under US law.
However, the appeals court judges ruled that the 1949 convention on the rights of prisoners of war did not apply to al-Qaeda members.
About 500 prisoners are held at Guantanamo Bay, many of them since 2002.