BAGHDAD -- The threat of chemical attacks hung over Iraq yesterday after terrorists exploded three chlorine-gas bombs in western Iraq, killing at least two persons and injuring 350 others, including children, the U.S. military said.

Six coalition forces were treated for exposure to the gas. A military spokesman said other chemicals have been found recently, stockpiled by insurgents.

The suicide bombings in Anbar province appeared to mark a growing power struggle between Sunni Muslims in Anbar province west of Baghdad, where some tribes have broken with al Qaeda-linked insurgents.

The attacks occurred Friday evening as two dump trucks and one pickup truck containing chlorine exploded within hours of each other near the Sunni towns of Fallujah and Ramadi.

Military spokesman Lt. Col. Christopher Garver said the chlorine used was not weapons-grade and appeared to be geared toward causing fear and panic rather than massive deaths.

"This is regular industrial chlorine. When these terrorists use this regular chemical in car-bomb manufacture, much of the chemical is destroyed in the explosion. These are not effective weapons for causing casualties," Col. Garver said.

The first suicide truck bomb detonated its load at a checkpoint northeast of Ramadi at 4:11 p.m. Two hours later, another explosion took place just south of Fallujah, near the town of Amiriyah.

Two policemen died in that attack, local police reported.

Thirty-seven minutes later, a third blast took place about three miles south of Fallujah in the Albu Issa region when a suicide bomber detonated a dump truck carrying a 200-gallon chlorine tank rigged with explosives.

Amiriyah residents exposed to the chlorine were treated for symptoms ranging from minor skin and lung irritation to vomiting, the military said.

There have been five suicide car bombs using chlorine gas in western Anbar province since Jan. 28, marking a new turn in the ever-evolving conflict in Iraq.

Col. Garver said U.S. military forces had found other stockpiles of chemicals in a car-bomb factory just east of Fallujah...