Afghan police say two civilians have been killed after a suicide car bomber blew himself up near a convoy of foreign troops.

Police said Saturday that at least four other civilians were wounded in the attack just west of Kandahar city in southern Afghanistan.

Afghan officials also said they are checking reports of heavy civilian casualties during U.S. coalition air strikes in southern Helmand province Thursday.

The officials say the air strike occurred in the province's northernmost Baghran district. A provincial police chief, Mohammad Hussein Andiwal, said Friday there were heavy casualties, but that he did not know how many militants and civilians were killed.

The U.S. military disputes the reports. A military statement says there were no civilians in the area when coalition forces conducted a precision air strike against two Taleban commanders conducting a leadership meeting.

The military says the fate of the commanders is unknown.

Some Afghan officials said the strike hit people who had gathered to watch the Taleban hang two men accused of spying for the government. Other reports dispute that account, quoting residents as saying victims were either preparing for picnics or going to a shrine.

Hundreds of civilians have been killed during NATO and U.S. military operations against insurgents. Angry Afghans have protested and President Hamid Karzai has called the situation unacceptable.

The issue is likely to be high on the agenda of an upcoming meeting between President Bush and Mr. Karzai at the Camp David presidential retreat near Washington.

Some information for this report was provided by AFP and AP.