Veteran US war correspondents say that while the rules appear to offer unprecedented freedom to report the facts, on closer scrutiny the US military could enforce draconian restrictions on coverage of any operations in the region.

The rules relate to "embedded" reporters - journalists who agree to give up a certain degree of freedom in return for permission to travel with units of the US military.

Around 500 embedded journalists are expected to accompany the US-led coalition forces in any attack on Iraq.

The Pentagon, which issued the guidelines last week, was initially praised for its light touch approach to ground rules for reporting a second Gulf war, particularly for its apparent agreement not to censor or review articles or broadcast footage filed by the media.

There are now serious concerns, however, that hidden in the document circulated to the press are a number of clauses that could result in a false or sanitised picture of events being presented to the world.

Senior journalists are concerned that mistakes made in the last Gulf war must not be repeated. In that conflict the use of precision or smart bombs was presented as a fail-safe way to prevent civilian casualties by the military and media.

By the end of the war it had emerged that only a small number of "smart weapons" had been used and there had been significant "collateral damage" or civilian casualties.

Sydney H Schanberg, the celebrated former correspondent for the New York Times, whose activities in Vietnam and Cambodia were featured in the film The Killing Fields, said this week that the rules were ambiguous and clearly designed to ensure "good PR" for the military.

In an interview with Editor & Publisher magazine, Schanberg said: "If I were an editor and I received this document, I'd be on the phone to the Pentagon for clarification within 10 minutes. I'd be saying 'what do you mean by that?'"

In one section of the document, the Pentagon says there is "no general review process for media products".

But in a later section it says: "If media are inadvertently exposed to sensitive information they should be briefed after exposure on what information they should avoid covering."

It adds that where a military commander believes it would be beneficial to the interests of the Department of Defence to allow journalists to see sensitive information that would normally be restricted, reporters must agree to a security review of their coverage.

"Agreement to security review in exchange for this type of access must be strictly voluntary and if the reporter does not agree, the access may not be granted," the guidelines state.

Schanberg advised editors to apply for fewer embedded slots and leave their best reporters to their own devices.

He added that another clause stating that all interviews with servicemen and women should be on the record was a clever way of preventing military from telling the truth.

In Vietnam, he said, "most things guys really wanted to tell you were not on the record" and military staff would fear disciplinary action for saying too much.

The Pentagon's rules also prevent journalists from using their own transport.

Another seasoned US war reporter, Chris Hedges, who reported from the last Gulf war, warned this would mean most of the press would only get to see what the military wanted them to.

Hedges added that given the "derogatory comments" made about the press by Donald Rumsfeld, the US defence secretary, "how can anyone think this is a guy who is going to allow the press to operate freely in this war?"

Another section prevents reporters from carrying their own firearms. In the recent conflict in Afghanistan, Geraldo Rivera, the moustachioed daytime TV host turned Fox News correspondent, became notorious for carrying a gun.

US defence officials are clearly concerned about negative coverage of the war both at home and in the UK.

The introduction to the document says: "Media coverage of any future operation will, to a large extent, shape public perception of the national security environment now and in the years ahead.