WASHINGTON >> New Defense Department guidelines allow commanders to punish journalists and treat them as “unprivileged belligerents” if they believe journalists are sympathizing or cooperating with the enemy.

The Law of War manual, updated to apply for the first time to all branches of the military, contains a vaguely worded provision that military commanders could interpret broadly, experts in military law and journalism say. Commanders could ask journalists to leave military bases or detain journalists for any number of perceived offenses.

“In general, journalists are civilians,” the 1,180-page manual says, but it adds that “journalists may be members of the armed forces, persons authorized to accompany the armed forces, or unprivileged belligerents.”

A person deemed “unprivileged belligerent” is not entitled to the rights afforded by the Geneva Convention, so a commander could restrict from certain coverage areas — or even hold indefinitely without charges — any reporter considered an “unprivileged belligerent.”

The manual adds, “Reporting on military operations can be very similar to collecting intelligence or even spying. A journalist who acts as a spy may be subject to security measures and punished if captured.” It is not specific as to the punishment or under what circumstances a commander can decide to “punish” a journalist.

Defense Department officials said the reference to “unprivileged belligerents” was intended to point out that terrorists or spies could be masquerading as reporters, or warn against someone who works for jihadist websites or other publications, such as al-Qaida’s Inspire magazine, that can be used to encourage or recruit militants.

Army Lt. Col. Joe Sowers, a Pentagon spokesman, said it was not the Defense Department’s intent to allow an overzealous commander to block journalists or take action against those who write critical stories.

“The Department of Defense supports and respects the vital work that journalists perform,” Sowers said. “Their work in gathering and reporting news is essential to a free society and the rule of law.”

But Ken Lee, an ex-Marine and military lawyer who specializes in “law of war” issues and is now in private practice, said it was worrisome that the detention of a journalist could come down to a commander’s interpretation of the law.

If a reporter writes an unflattering story, “does this give a commander the impetus to say, ‘Now you’re an unprivileged belligerent?’ I would hope not,” Lee said.