WASHINGTON (AP) — A federal judge on Thursday weighed the fate of a U.S. citizen who has been accused of working with Islamic State militants in Syria, but never charged.

The Trump administration has been holding the unidentified citizen at a U.S. military facility in Iraq since he surrendered on the Syrian battlefield more than seven months ago. The man, who once lived in Louisiana, is being held as an enemy combatant and the government now wants to transfer him to a third country — presumably Saudi Arabia, where he has dual citizenship.

Court documents filed by the government say that when he surrendered to U.S.-backed Syrian Democratic Forces, he was carrying thumb drives containing thousands of files. There were 10,000 or more photos — some depicting pages of military-style manuals. There also were files on how to make specific types of improvised explosive devices and bombs.

The American Civil Liberties Union, which is representing him, claims he was in Syria to chronicle the conflict and was trying to flee the violence when he gave himself up in September 2017. The ACLU claims the government has not provided any evidence that he took up arms against the United States and notes that he was imprisoned by IS. The detainee said he had press credentials to do freelance writing about the conflict in Syria, although the FBI hasn't found any published articles or blogs he authored.

ACLU attorney Jonathan Hafetz has argued that any transfer violates the detainee's constitutional and legal rights because the government hasn't proved that it legally detained him in the first place.

"When it comes to the rights of an American citizen, it's not 'Let's Make a Deal,'" Hafetz told the court.

As required by the court, the government gave 72 hours' advance notice of its intent to transfer the detainee to a third country. The detainee could be moved to Saudi Arabia, where he has dual citizenship, according to a U.S. official who was not authorized to discuss the issue and spoke only on condition of anonymity.

The ACLU wants the judge to block the transfer and hopes she will rule before the 72 hours expires at 8:06 p.m. Thursday.

Before the court adjourned to a closed session, U.S. District Judge Tanya Chutkan appeared to side with the ACLU.

She said the government was asking her to allow the U.S. to transfer an American citizen, who has not been charged with a crime, to another country. She said there was no indication as to when or if the receiving country would ever release him.

"That's just more indefinite detention," she said.

"It's not release if you are just giving him to another jailer," the judge said.

The government acknowledged that the receiving country could continue to hold the detainee for as long as it determined was necessary. James Burnham, a lawyer representing the government, said the receiving country has a strong interest in the detainee and that U.S. relations with the nation could be harmed if the transfer is not allowed to go through.

The detainee's legal quandary has become a test case for how the government should treat U.S. citizens picked up on the battlefield and accused of fighting with IS militants.

"Given this individual's dual Saudi citizenship, and provided the U.S. has obtained appropriate humanitarian assurances, the judge may find a legal basis for the transfer," said Nate Jones, a former staff member of the National Security Council and founder of Culper Partners consulting group.

The government claims presidential authorities as well as congressionally approved war powers written after 9/11 provide the legal basis to hold the detainee as an enemy combatant linked to IS. The ACLU argues those war powers, known as the Authorization for Military Force, pertain to al-Qaida and the Taliban and don't apply in the battle against IS.

"If the judge does allow it to proceed, the U.S. government may dodge a bullet by avoiding judicial scrutiny of some complicated and very consequential legal questions, including the rights afforded to Americans held in military detention, whether the AUMF extends to IS and authorizes his detention at all, and whether there was sufficient evidence to justify it even if it does," Jones said.