WASHINGTON, Feb 6: The Pentagon is writing rules of engagement to allow US forces to use non-lethal riot control agents to minimize civilian casualties if the United States goes to war in Iraq, US Defence Secretary Donald Rumsfeld said on Wednesday.

But Rumsfeld said treaty restrictions and other laws that bar the use of riot control agents in warfare without a presidential waiver have made the process “very complex”.

“We are doing our best to live within the straitjacket that has been imposed on us on this subject,” he said at a hearing of the House Armed Services Committee.

US military planners fear that US forces may have to contend with massive movements of panic-stricken civilians if Iraq uses of chemical or biological weapons, or hostile crowds if an invading force meets popular resistance.

Army General Tommy Franks, the commander of US forces in the region, has drawn up a plan that seeks to achieve US military objectives with the least interference with civilians, Rumsfeld said.

The plan deals with “a host of very unpleasant contingencies,” he said.

“Absent a presidential waiver, in many cases our forces are allowed to shoot somebody and kill them but they are not allowed to use a non-lethal riot control agent under the law,” he said. “It is a very awkward situation.

The 1997 Chemical Weapons Convention bars the use of riot control agents as a method of warfare, and the Geneva Conventions place other restrictions on the military’s treatment of civilians.

A 1975 US executive order, however, says the use of riot control agents would be permissible in certain situations, for instance when civilians are used to mask or screen attacks and civilian casualties can be avoided.

Although intended to save civilian lives, the use of non-lethal agents is controversial.

Russian authorities discovered that last November when they tried to end a Chechen hostage-taking at a Moscow theatre by pumping in opiate gas to put the hostagetakers to sleep. The gas killed 129 captives. President George W. Bush, however, defended the Russian action.

Rumsfeld said the use of non-lethal agents was “perfectly appropriate” in some situations encountered by US forces in Afghanistan: transporting dangerous prisoners on aeroplanes, or flushing out caves where fighters were hiding with women and children.

But he said writing simple rules for what were often complex and stressful situations has proven difficult.

“We have tangled ourselves up so badly on this issue,” he said.

He and General Richard Myers, the chairman of the Joint Chiefs of Staff, wrestled for more than hour last week trying to fashion rules that were clear enough that a soldier on the front line could “in a second or two make a decision about what they can do, what they can’t do.”

Myers said military commanders also were working out ways of dealing with the potential use of civilians as human shields at Iraqi targets, or Iraqi civilians taking up arms against US forces.

“If the regime were to use civilians as human shields and so forth it’s a different matter and you would have to address that differently. If they take up arms, they are combatants. They will be treated as such,” he said. —AFP