The US military on Tuesday transferred an "enemy combatant" to civilian custody, the Justice Department said.
The man, Ali Saleh Kahlah al-Marri, a 43-year-old Qatari national, is now in the custody of US Marshals Service after being released from the Naval Consolidated Brig in South Carolina, the department said in a written statement.
He was arrested in December 2001 while studying in a US college and had been detained by the US military since then as an "enemy combatant" without any charges.
The US military accused al-Marri of being an al-Qaida "sleeper agent" in the United States, and had been trained at a terror camp in Afghanistan, met al-Qaida leader Osama bin Laden, and "volunteered for a martyr mission."
The American Civil Liberty Union had filed a case on his behalf, challenging the US President's unilateral authority to detain him indefinitely and without charges.
On last Friday, the US Supreme Court granted the Obama administration's request to dismiss al-Marri's challenge.
Meanwhile, President Barack Obama ordered the US military to transfer him to civilian custody, saying it was "in the interest of the United States."
Al-Marri is expected to face a trial on terrorism charges in a civilian court.
However, the Supreme Court's ruling means there's no resolution of the larger issue of the US President's power to detain people accused of terrorism and other crimes in the United States.