At least one person has been killed and more than 20 others injured after two commuter buses were hit by a roadside bomb in central Baghdad, Iraqi police say.
One of the buses bore the brunt of the blast
"We have one dead, 22 injured, all Iraqis. It was a bomb planted on a roadway," an Iraqi police lieutenant told Reuters news agency.
Witnesses said an explosive device planted at the side of the road went off when a US patrol passed by. It missed the American soldiers but hit two minibuses instead.
Several people, including a young girl, had leg and arm injuries.
The blast happened at about 0930 local time (0530 GMT) in the central Baghdad neighbourhood of al-Dameer.
Reuters also reported a blast at a cinema in the northern city of Mosul.
The news agency quoted local sources as saying several people were wounded.
Meanwhile, the condition of Iraqi Governing Council member Aqila al-Hashimi, who was shot in Baghdad by unidentified gunmen last week, has worsened, the Associated Press news agency quoted a council spokesman as saying.
Doctors were "trying their best" to save her life, Entifadh Qanbar said.
Shopkeeper Ala Saddam said his store was rocked by the blast which struck the buses in Baghdad.
"We were sitting inside the store... when the explosion went off," he said.
"The glass shattered in my shop. We went out and saw the two small buses had been hit," he added.
There have been a string of bomb attacks in Baghdad recently
The police later said the bomb appeared to be a home-made device.
The BBC's Jill McGivering in Baghdad says that roadside bombs, often controlled remotely, have become a common weapon against coalition forces.
She says attackers - concentrated in central Iraq - are thought to be disaffected former Baath Party members loyal to Saddam Hussein and working to undermine the coalition's authority.
It is the latest in a series of attacks in the capital in recent days.
On Monday, a bomb attack apparently targeting the United Nations building, killed two people, including the bomber.