EXTRA INSURANCE

A U.S. Army patrol stops suspicious vehicles on the edges of this insurgent-controlled city.

Some 500 yards away, lying prone and hidden in the sand, two expert marksmen stalk Iraqis emerging from cars through the cross-hairs of their rifles.

If they detect a sudden, hostile move, the snipers should be able to kill the assailant with a single bullet before the patrol itself can react.

''We can't get enough of them,'' says Capt. Damien Mason, from Maui, Hawaii, a company commander who ordered the two shooters into position. ''Snipers are vital in this kind of warfare.''

Mason's commanding officer, Lt. Col. Karl Reed, describes snipers in Iraq as a ''political weapon,'' ideally able to isolate and knock out combatants without harming civilians whom insurgents often use as human shields...

''It's more personal than regular combat. You see the man's expression before you pull the trigger, then the blood and the fall,'' says Cpl. Omar Torres, a sniper with the 2nd Infantry Regiment, 1st Infantry Division.

The 23-year-old soldier and others rate their Iraqi counterparts low on training and ingenuity, saying opposing snipers invariably use upper stories of houses or rooftops and aren't armed with particularly accurate weapons. Nonetheless, they're among the main killers of U.S. forces after roadside bombers.

Torres, of Waterbury, Conn., is one of only five fully qualified snipers in the regiment's 2nd Battalion, having gone through the army's rigorous sniper school at Ft. Benning, Ga.

Up to 70 percent of a class fails the five-week course. Successful students become masters of camouflage, stealth and ability to identify hostile faces in a crowd by their expressions and movements.