The US military said it killed two Iraqi fighters in the clashes which took place early on Sunday around Tal Afar near the city of Mosul.
There were no American casualties, the military added.
A doctor at Tal Afar hospital said the majority of the wounded were women and children, many hit by shrapnel.
Police said the clashes occurred when two US convoys were attacked, after which US troops returned fire heavily in the village neighbourhoods.
Meanwhile, a pipeline exploded in Iraq's south Rumaila oilfield on Sunday, days after several pipelines in the same area were sabotaged.
A Reuters photographer saw fire and smoke rising from the pipeline near the city of Basra after hearing a blast.
It is not known whether the explosion could further cut exports already disrupted by sabotage.
Employees attempt to control
the Rumaila oilfield fire
Before the blast, exports from Iraq's southern terminals on Sunday were running at a rate of 1.4 million barrels per day, shipping agents said.
That was up to 30% lower than last week, when 10 pipelines linking the north and south Rumaila fields to storage tanks and a pumping station were hit.
Meanwhile, Aljazeera has learnt that US forces and the Iraqi interim government have held negotiations with representatives of Shia leader Muqtada al-Sadr in an attempt to enforce a ceasefire in north-east Baghdad.
At least 15 people were killed on Saturday during clashes and a US bombardment of Falluja and Sadr City.
Iraq's Prime Minister Iyad Allawi on Saturday vowed to crush militiamen who refuse to disarm.
"We will confront this with force ... It seems that there are some elements in the al-Mahdi Army that insist on making things more difficult in Iraq outside of Najaf," he told Iraq's state-run Iraqiya television.
Najaf has been battered by
weeks of bombardment
One day earlier, al-Sadr evacuated his mosque bastions in the cities of Kufa and Najaf, where his fighters disarmed, ordered by Iraq's Shia Muslim spiritual leader Grand Ayat Allah Ali al-Sistani to end weeks of combat.
But six people were killed and 92 wounded in the last 24 hours of clashes between al-Sadr's supporters and US troops in his Baghdad stronghold of Sadr City, said medics at three hospitals.
Al-Sistani's five-point ultimatum for peace in Najaf made no mention of Baghdad or any other southern Shia cities where the al-Mahdi Army has clashed with occupation forces and Iraqi interim security forces.