Two American soldiers have been killed and four wounded in an attack in Baghdad, the US military says.
Sadr City was also the scene of an attack on a police station
The troops from the 1st Armoured Division were on patrol in the Sadr City area of the Iraqi capital, when they were ambushed on Thursday evening.
The latest deaths bring to 94 the number of American soldiers killed in attacks in Iraq since President George W Bush declared an end to major combat operations in May.
Earlier on Thursday, at least 10 people died in a suicide bombing at a police station also located in Sadr City - a mainly Shia district.
The BBC's Jon Brain in Baghdad says the ambush happened during a night of tension in the area, as US troops continue their investigation into the bombing.
In some cases house-to-house searches provoked anger, and at one stage soldiers exchanged fire with armed men guarding a local Shia cleric.
Our correspondent adds that although there is no suggestion that Shias have been responsible for any of the attacks on US forces, a growing number are angry at what they view as the coalition's failure to adequately protect their communities.
Hundreds of officers had been waiting to receive salaries when the attack on the police station took place.
A car drove at speed through the gate, despite shots fired by guards.
The blast killed three policemen, five civilians and two men in the car.
"I ran and got hit in the leg," said police officer Khalid Sattar Jabar, 25, from his hospital bed. "When I looked back, all I could see was fire."
Iraq's police force has been the target of a series of attacks since the US-led coalition began running the country.
In the United States, President Bush's drive for funding to reconstruct Iraq and Afghanistan received crucial support from a key Congressional committee, the House Appropriations Committee.
Members gave their President over $18bn of the $20.3bn he had asked for to help rebuild Iraq.
The BBC's Michael Buchanan, in Washington, said that among the things they cut out were plans to provide litter trucks, two new prisons and a hospital in Basra.