Nation & World

KABUL, Afghanistan — A powerful car bomb detonated outside a police station in the southern city of Kandahar killed seven people on Sunday, including five police officers and a child, Afghan provincial officials said.

The explosion came a day after the release of a United Nations report saying that civilian casualties had reached a wartime high and pointing out the extent to which ordinary Afghans' daily lives are increasingly punctuated by violence. Insurgents are blamed for the bulk of the deaths.

At least 19 people were injured in the Kandahar blast, including three children, two women and six police officers, said provincial spokesman Zalmay Ayoubi.

Kandahar, the hub of Afghanistan's south, remains volatile despite a massive U.S.-led military push in the last two years. American troop strength peaked last year at over 100,000 and is to fall this year to about 68,000 as the North Atlantic Treaty Organization force prepares to wind down its combat role next year.

In northern Afghanistan, officials in Sar-e-Pul province reported that a U.S. soldier had shot and killed an Afghan guard at a military base and called the fatal incident the result of a misunderstanding. The American apparently believed the guard was about to attack him, according to Said Anwar Rahmati, the provincial governor.

The incident underscored the climate of deep mistrust between Western and Afghan troops in the wake of dozens of "fratricidal" attacks in the last five years.

Four French troops were killed and more than a dozen others wounded last month by an Afghan soldier, and France announced days later that it was cutting short the deployment of its forces in Afghanistan.