The first trial at Guantanamo under US President Barack Obama has been suspended after a lawyer fell ill.
Canadian citizen Omar Khadr, 23, is accused of throwing a grenade that killed a US soldier during a gun battle in Afghanistan in 2002, when he was 15.
His US-appointed lawyer, who recently underwent gall bladder surgery, fainted during opening arguments and was flown back to the US for treatment.
The ex-child combatant is the youngest detainee in the US prison on Cuba.
The Associated Press news agency said the trial would be suspended for at least 30 days while the lawyer, Jon Jackson, was treated.
Mr Jackson collapsed in the courtroom on Thursday.
His deputy, Bryan Broyles, said he expected the same jury to sit on the trial when it re-opened.