A federal judge is ordering a prominent Palestinian Arab activist, Sami Al-Arian, released pending a trial on criminal contempt charges, but she has refused to block immigration authorities from detaining Al-Arian as a prelude to his deportation.

The upshot of the ruling from Judge Leonie Brinkema at a bail hearing at Alexandria, Va. this morning seemed to be that Al-Arian will stay behind bars, at least for now. However, the decision puts the government in the odd posture of detaining a man for a deportation authorities have no immediate intention of carrying out.

“It was a very good day,” one of Al-Arian’s lawyers, Jonathan Turley, said in a brief telephone interview after the court session. “She agreed with us that he’s not a flight risk and not a danger to the community, that that was not a barrier to bail.”

Mr. Turley said Judge Brinkema also said she was picking up “strange signals” from the case and she warned the government that it should not be using the contempt charges to delay Al-Arian’s deportation.

The prosecutor at today’s hearing, Gordon Kromberg, declined to comment for this article.

Under a plea agreement which resolved a terrorism-support case against Al-Arian in 2006, the government agreed to deport him expeditiously once he finished serving his criminal sentence in that case. An earlier trial in that case, held in federal court in Tampa, Fla., resulted in some acquittals for Al-Arian while jurors could not reach a unanimous verdict on other charges.

After pleading guilty, Al-Arian was called to appear before grand juries in Virginia investigating a web of Islamic charities, including a think tank, the International Institute for Islamic Thought. Al-Arian refused to testify before the panels, asserting that his plea agreement precluded the government from forcing his cooperation. However, two appeals courts have rejected that argument. Al-Arian spent more than a year in jail for civil contempt for defying the grand juries. His 57-month criminal sentence was put on hold repeatedly while he was jailed for contempt, but the criminal sentence ran out in April.

Al-Arian has insisted he is being persecuted by Justice Department officials sore over the disappointing result of the Tampa trial. Last year, he went on a hunger strike for 57 days and lost over 40 pounds, according to his supporters.

Mr. Turley said Mr. Kromberg acknowledged that some of the questions the government wants to ask Al-Arian pertain to issues raised at his Florida trial. Al-Arian’s lawyers fear such a tactic would be an attempt to retry the Florida case by eliciting denials that could become the basis for perjury charges.

A trial on the criminal contempt charges is set for August 13. The law sets no specific penalty for a conviction. In theory, Al-Arian could face life in prison, or even the death penalty.

Al-Arian, who was born in Kuwait, is a former computer science professor at the University of South Florida who was a prominent figure in Arab and Muslim political efforts in America, before he was indicted in 2002 and accused of acting as a top leader of Palestinian Islamic Jihad.

Al-Arian has been in government custody since he was indicted six years ago. His wife and some of his children recently moved to Egypt. That country has agreed to accept him if the deportation goes forward, Mr. Turley said.