US troops fired on a march protesting another shooting
US troops have opened fire on protesters for a second time this week in the town of Falluja, 50 kilometres (35 miles) west of Baghdad.
Ahmed al-Taha, a senior official at Falluja's main hospital, said two people were killed and eight wounded during a march to protest against the deaths of 13 people on Monday night.
The dead Iraqis had head wounds caused by bullets or shrapnel, he said.
US military spokesmen say troops were fired on first in both incidents, which occurred outside facilities being used by US paratroops in the town.
About 1,000 local people from the town - a Sunni Muslim former stronghold of Saddam Hussein's Baath party - had marched down the main street to the battalion headquarters of the US 82nd Airborne Division to protest against Monday's deaths outside a primary school.
Stones and shoes were hurled at the HQ, situated in a compound formerly occupied by the Baath party, and troops opened fire at about 1030 local time (0630 GMT), dispersing the crowd.
There was confusion over whether guards inside the compound or troops from a passing US convoy fired the shots.
US Major Michael Marti said troops had opened fire after a convoy came under gun attack which began as protesters hurled stones at the vehicles.
"Then fire came from the crowd, directed at the convoy," he said.
"It was at that point that they returned fire... It was well-aimed fire."
But witnesses who spoke to the Associated Press news agency said there had been no gunfire from the direction of the protesters.
Jamal Shaqir Mahmood, the imam at the Grand Falluja Mosque, said people wanted American troops to leave the town or at least reduce their numbers.
"There is no [Iraqi] military presence here," he said.
"Why is there an American military presence? We just want a reduction in the numbers."