Iraqi police and witnesses say U.S. forces have killed 10 civilians and wounded several others during a raid on a building in a mostly Sunni neighborhood in southern Baghdad.
Police say an unknown number of people were detained after U.S. helicopters attacked the building during the pre-dawn raid in the Sihha district.
There has been no comment from the U.S. military.
On Thursday, the military said it was investigating the deaths of nine civilians in Babahani, a village south of Baghdad, where U.S. forces had been conducting operations against al-Qaida in Iraq.
Meanwhile, the U.S. military says a senior leader of al-Qaida in Iraq has been killed in coalition raids.
In a videoconference to Pentagon reporters from Iraq Friday, Brigadier General Joseph Anderson identified the man as Abu Usama al-Tunisi and described him as a likely successor to al-Qaida in Iraq's current leader, Abu Ayyub al-Masri.
General Anderson said Tunisi was killed Tuesday near the city of Musayyib, about 60 kilometers south of Baghdad. Musayyib is an area dubbed the "triangle of death" because of frequent attacks on U.S. and Iraqi forces.
On the political front, Iraqi Prime Minister Nouri al-Maliki says a U.S. Senate resolution calling for the creation of a loose, de-centralized system of government in Iraq would hurt the country.
On Thursday, the Arab League and Iraq's Shi'ite vice president, Adel Abdul-Mahdi, also rejected the resolution. Mahdi said it is up to Iraqis to decide the future of their country.
The non-binding resolution, which passed earlier this week, calls for a political settlement that would essentially divide Iraq into three ethnic, semi-autonomous regions controlled by Sunni Arabs, Shi'ites and Kurds.
Some information for this report was provided by AFP and Reuters.