Iraqi authorities say sectarian violence claimed more lives in Baghdad Sunday.

They say gunmen killed nine people in the homes of two Shi'ite families in a mixed Sunni-Shi'ite district of southwest Baghdad.

Police say gunmen killed five brothers in one house after separating them from their female relatives. In the other house, the gunmen killed a policeman and his three sons.

Fighting was also reported in a nearby district, Al-Amil between Shi'ite militiamen and a Sunni tribe. At least one person was killed and six were wounded.

And a roadside bomb killed a U.S. soldier west of the capital.

Donald Rumsfeld (r) with U.S. troops in Iraq

Meanwhile, outgoing U.S. Defense Secretary Donald Rumsfeld has made a surprise visit to American troops in Iraq to thank them for their sacrifices.

He told the troops they can win on the battlefield, but a political process must also help determine the future of the Iraqi people.

Rumsfeld leaves office later his month. He submitted his resignation in November, one day after the Republicans lost control of Congress in mid-term elections. His successor will be former CIA director Robert Gates. The U.S. Senate confirmed Gates on Wednesday.

Some information for this report was provided by AP.