NEWARK, N.J. — A former U.S. attorney general, Janet Reno, and seven other former Justice Department officials challenged the Bush administration’s bid to try suspected terrorist Ali Saleh Kahlah al-Marri, a foreign national living in America when he was arrested, before a military commission.

Ms. Reno and the others said the Bush administration is trying to set a dangerous precedent that would let the government indefinitely imprison any non-American citizen considered an enemy. The former American officials were joined by at least four human rights groups making similar arguments.

The administration is “asserting the right to hold putative enemy combatants arrested in the United States indefinitely whenever it decides not to prosecute them criminally,” Ms. Reno, six former U.S. attorneys, and a former deputy solicitor-general said in a “friend-of-the-court” brief.

Mr. Marri, 41, was the first defendant removed from the American criminal justice system and deemed an illegal enemy combatant. He was studying in America and living in Illinois when he was arrested in late 2001. The Justice Department unsealed the indictment in December 2002, and he was declared an enemy combatant about six months later. A citizen of Qatar, Mr. Marri has been held at a U.S. Navy Prison in South Carolina since June 2003.

The Justice Department said it stands by its decision to try Mr. Marri as a suspected terrorist outside the criminal court system.

“These are complex and difficult legal issues,” a Justice Department spokeswoman, Kathleen Blomquist, said in an e-mailed statement yesterday. “While we respect the right of other legal minds to be heard on these issues, we believe we are on firm legal footing.”

The Justice Department said a new anti-terrorism law, the Military Commissions Act, gives terrorism suspects such as Mr. Marri no right to challenge their imprisonment.