Witnesses and security officials in Baghdad say U.S. forces have staged air raids on a Shi'ite neighborhood of the city, killing at least five people.
Some reports from Baghdad say the U.S. air strike on the Shi'ite enclave of Shula may have killed as many as nine people.
A U.S. military spokesman said he could not comment on an ongoing operation.
On Monday, police found the bodies of 46 people in and around Baghdad. Most had been tortured in suspected sectarian attacks.
Also in Baghdad, Iraqi police said a suicide bomber struck a bus in a largely Shi'ite district of Shaab, killing at least 11 people.
A bomb blast in the city killed two U.S. soldiers.
Amid the violence, the U.S. commander in the Middle East General John Abizaid met with Iraqi Prime Minister Nouri al-Maliki.
News reports say they discussed the security situation in Iraq.
General Abizaid is the third top U.S. official to visit Iraq in recent weeks.
The meeting comes after Prime Minister Maliki announced, on Sunday, that he would reshuffle his cabinet. It also comes after last week's U.S. elections, in which Democrats won control of both houses of Congress. Many Democrats support a phased U.S. withdrawal from Iraq.
Some information for this report was provided by AP.