A US military convoy has come under fire in the flashpoint Iraqi town of Falluja, setting a truck carrying ammunition on fire.
A photographer at the scene said a rocket appeared to hit the truck causing a huge explosion. Gunmen fired on US troops caught in the blast and American soldiers returned fire.
"I saw (American) casualties and gunmen fired on them," said photographer Akram Saleh who was driving close to the convoy when the attack took place. "American soldiers fired back."
He said the explosion set the truck and a Humvee ablaze, sending black smoke billowing into the air.
A US military spokesman in Baghdad could not immediately confirm the incident.
Falluja, about 40 miles west of Baghdad, is part of the so-called "Sunni Triangle", the heartland of resistance to the US-led occupation where American soldiers come under daily attack.
