Two United States Blackhawk helicopters have crashed while landing in northern Baghdad.
One Iraqi soldier was killed and two American and two Iraqi soldiers were wounded in the crashes.
The US military says hostile fire was not immediately suspected in the incident.
But Baghdad police said a US helicopter was downed by gunfire and there was fighting in the area after it crashed.
The police said the fighting was between local militias and American and Iraqi forces.
Meanwhile, a suicide bombing in northern Iraq has killed at least eleven people. The bomber blew himself up inside a house in the city of Mosul.
And in Afghanistan, Britain's top commander has warned that it may not be possible to win the war against the Taliban, suggesting that a deal with the Islamic militants may have to be reached to end their insurgency.
Brigadier Mark Carleton-Smith said that if the Taliban were willing to talk, then that might be "precisely the sort of progress" needed to end the insurgency.
"We're not going to win this war. It's about reducing it to a manageable level of insurgency that's not a strategic threat and can be managed by the Afghan army," he said.
He said his forces had "taken the sting out of the Taliban for 2008" but that troops may well leave Afghanistan with there still being a low level of insurgency.
NATO commanders and diplomats have been saying for some time that the Taliban insurgency cannot be defeated by military means alone and that negotiations with the militants will ultimately be needed to bring an end to the conflict.
"If the Taliban were prepared to sit on the other side of the table and talk about a political settlement, then that's precisely the sort of progress that concludes insurgencies like this," Brigadier Carleton-Smith said.
"That shouldn't make people uncomfortable."