WASHINGTON — The Bush administration said yesterday that Guantanamo Bay prisoners have no right to challenge their detentions in civilian courts and that lawsuits by hundreds of detainees should be dismissed.

In court documents filed with the U.S. Court of Appeals for the District of Columbia Circuit, the Justice Department defended the military’s authority to arrest people oversees and detain them indefinitely without access to courts.

It’s the first time that argument has been spelled out since President Bush signed a law last month setting up military commissions for the thousands of foreigners being held in American prisons abroad.

Mr. Bush hailed the law as a crucial tool in the war on terrorism and said it would allow prosecution of several high-level terror suspects.

Human-rights groups and attorneys for the detainees say the law is unconstitutional. Prisoners normally have the right to challenge their imprisonment.

The Justice Department said yesterday that detainees have no constitutional rights. Giving military detainees access to civilian courts “would severely impair the military’s ability to defend this country,” government attorneys wrote.

“Congress could have simply withdrawn jurisdiction over these matters and left the decision of whether to detain enemy aliens held abroad to the military,” the Justice Department wrote.