The commander of U.S. forces in Iraq says Iran is fueling instability in neighboring Iraq by funding and training Shi'ite extremist groups in the country.
General Ray Odierno told CNN on Sunday that Iran does not want Iraq to become a strong democratic country. He said Iran would rather see Iraq become a "weak governmental institution."
Odierno also said it would take a "complete failure" of Iraq's security forces for the U.S. to resume combat operations there. He said Iraqi forces have done so well for so long that he finds their failure unlikely.
Meanwhile, the U.S. military says an American soldier was killed in southern Iraq's Basra province on Sunday.
The soldier was the first fatality among U.S. troops in Iraq since the last American combat brigade left the country last Thursday.
Smaller U.S. combat units remain in Iraq but are scheduled to leave by the end of this month.
About 50,000 U.S. troops will stay in Iraq until the end of 2011 as a stability force.
Their focus will be training Iraqi soldiers and performing counter-terrorism operations, but they will be fully capable of fighting if they are attacked or if Iraqi forces need help.
More than 4,400 U.S. military personnel have been killed in Iraq since war began in March 2003 with a U.S.-led invasion that eventually toppled Iraq's Saddam Hussein.
Late Saturday, Iraqi police in the city of Nasiriya used water cannon to disperse stone-throwing demonstrators angry about severe shortages of electricity.
Officials say at least nine protesters and six police were hurt in the clashes.
Public anger at power shortages has increased in June, July and August as summer temperatures regularly reach 50 degrees Celsius.
Violent protests in Nasiriya and Basra in June left two protesters dead and wounded a number of police and civilians.
Some information for this report was provided by AP, AFP and Reuters.