US troops arrested more than 80 people in hotbeds of anti-US resistance, where a shadowy and loose alliance of former Baath party loyalists, Islamic militants, foreign fighters and criminals have caused mayhem in the post-Saddam Hussein (news - web sites) era.
The latest shootout between US troops and rebels in the town of Fallujah west of Baghdad resulted in the death of a married couple, said the dead man's brother and local police.
Fallujah residents and the US Army's 82nd Airborne Division reported the shelling Tuesday night of a US forward military base outside the tense city where soldiers come under frequent attack.
US paratroopers opened fire in response, both the military and locals said.
At this time, Mohammed Hassan Karht said he watched US soldiers shell his brother Ahmed's home, killing his brother and his sister-in-law, Siham Khalaf.
Police Lieutenant Ibrahim Ahmad said he went to the destroyed building and saw two bodies there.
But the US military could not confirm if the husband and wife had been killed during its retaliatory action.
"Paratroopers from the 82nd Airborne engaged the point of origin with MK-19 grenade launchers and small arms causing two personnel to flee into a nearby building which was also engaged and destroyed," a military statement said.
"They then cordoned off the area and searched the remnants of the building, finding no personnel or weapons. Upon questioning, civilians in the area reported two dead personnel were taken to a nearby hospital. No casualties have officially been confirmed by the coalition."
Meanwhile, Iraqi police were ambushed on the road between the northern oil refinery of Baiji and the town of Hawijah, 80 kilometres (50 miles) northeast of Kirkuk.