U.S. officials intend to return and release an American citizen accused of supporting the Islamic State back into Syria against his will, after holding him for nine months in U.S. military custody without charges.

The plan was revealed Wednesday night in a brief federal court notice in Washington in a case that has tested whether U.S. citizens captured on a battlefield as suspected “enemy combatants” have the right to challenge their detentions.

The planned release would take place in 72 hours and would be done over the objections of the man, who has not been named publicly, the government said. A longer sealed court filing also was entered in court.

The American Civil Liberties Union, which has been representing the man, said it will ask a court to block the release, which it condemned as “disgraceful” and a de facto “death warrant.”

The U.S. military in Iraq has held the unidentified man as a suspected Islamic State fighter since he was turned over to American forces in September after he was captured at a rebel Syrian Democratic Forces checkpoint in Syria and declared his U.S. citizenship.

The man grew up in Saudi Arabia and also had Saudi citizenship, court filings show.

The unusual case has raised significant questions about how the courts balance national security interests with the constitutional rights of U.S. citizens caught in conflict zones.

ACLU attorneys for months fought for — and won — the right to represent the man, arguing that because he is a citizen, the government should charge him with a crime that would be pursued in a U.S. courtroom or release him.

The man was questioned for U.S. intelligence purposes, but American officials have said they lack admissible evidence to charge him with a crime.

ACLU attorney Jonathan Hafetz said that although the government has effectively conceded that it has no reason to continue holding the man and that he does not pose a threat, “They want to dump an American citizen onto the side of the road in a war-torn country without any assurances of protection and no identification.”

The Trump administration has said the law provides the U.S. military with broad discretion to conduct battlefield operations, including the transfer of people captured overseas.

A spokesman for the Defense Department declined to comment, citing the pending litigation.

In court filings, Kathryn L. Wyer, a senior trial counsel for the Justice Department, called the Pentagon’s release plan “consistent with the traditional military practice employed in the United States Central Command area of responsibility and with the Department’s obligations under the law of war.”

Wyer said that although details remained sealed, the government told the ACLU that it gave the man a choice of release to a town or outside a refugee camp but that the man “would not agree” to its terms.

In April, U.S. District Judge Tanya S. Chutkan barred the government from ending the man’s U.S. custody by transferring him, also against his will, to the custody of a third country that had agreed to accept him and formally confirmed he would not face torture. References in the filing suggested the country was Saudi Arabia, although the country was not disclosed publicly.

Chutkan said it was “disingenuous” to call that a release, triggering a government appeal in May to the U.S. Court of Appeals for the D.C. Circuit, where a three-judge panel agreed the government cannot “forcibly — and irrevocably — transfer” the man and agreed any move would require 72 hours notice.

The ACLU has said the case could create a constitutional “black hole” if it gave the government carte blanche to hold any U.S. citizen traveling overseas, such as journalists or tourists.

ACLU attorneys have told the court that the man said he was not a combatant and was a freelance journalist at the time of his capture.

Chutkan was due to take up the ACLU’s underlying constitutional challenge to the man’s detention in the next two weeks.

Wednesday’s notice by Justice Department attorneys seemed intended to head off further litigation on that front while probably provoking a fresh round of appeals over when the government can forcibly release a citizen.

University of Texas law professor Stephen I. Vladeck said that while there is a plain legal distinction between transfer and release, courts have found that detainees have a right not to be released to a mob.

“I think the question for the district court is going to be whether the release the government has contemplated really will put Doe in significant jeopardy,” as the ACLU claims, Vladeck said.

He said the filing on the Syria release plan also suggests that whatever third country that had said it would accept the man had changed its position, or that the government was seeking to drop the case to avoid having to litigate thorny legal questions of the scope of its battlefield authority to hold citizens.

In a statement, the ACLU’s Hafetz noted the State Department has issued “do not travel” warnings for Syria, advising U.S. citizens who ignore them to leave DNA samples and draft a will.

“Our fight for our client’s right to due process has also become a fight for his right to life,” Hafetz said. “We’ll be asking the court to immediately intervene and ensure the safe release of our client.”

Paul Sonne contributed to this report.