A homicide car bomb exploded Sunday near a convoy carrying the governor of Afghanistan's southern Kandahar province, missing the apparent target but killing four civilians and wounding 13, officials said.

The bomber, driving a four-wheel-drive vehicle, detonated his charge as the motorcade of the provincial governor, Asaddullah Khalid, drove through the streets of Kandahar city, according to President Hamid Karzai's office.

Four civilians died in the blast, 13 others were wounded and Karzai "strongly condemned" the attack, the president's office said in a statement.

CountryWatch: Afghanistan

"The noble nation of Afghanistan recognizes these atrocities as the act of enemies of peace and reconstruction," the interior ministry said.

Two vehicles of the U.S.-led coalition were nearby when the blast occurred, but there were no casualties among the foreign forces, said coalition spokesman Maj. Quentin Innis. One vehicle was damaged.

Another coalition spokesman, Maj. Scott Lundy, said the coalition troops were on a patrol and were not linked to the governor's convoy.

Two destroyed vehicles were at the site of the attack, with the mangled body of the bomber still in the scorched wreckage of a black vehicle. A nearby coffee house was destroyed in the morning bombing.

A surge in fighting and attacks in Afghanistan since mid-May, particularly in southern regions like Kandahar province where the Taliban are strongest, has killed more than 400 people, most of them militants.

In other violence Sunday, coalition and Afghan troops cordoned off a village in southern Zabul province and then battled suspected Taliban fighters in one house, killing four suspected militants and capturing five, said Afghan army Gen. Rehmatullah Raufi.

There were no coalition or Afghan security force casualties, he said.

Also in Zabul, a roadside bomb hit an Afghan army vehicle, killing one soldier and injuring four, he said.

Suspected Taliban fighters attacked a police checkpoint overnight in southern Nimroz province, killing four police, said Mohammad Yousuf Stanizai, a spokesman for the Interior Ministry.

Two dead attackers were discovered after the fight, but there was no firm toll for militant casualties, he said.

Two other suspected Taliban fighters died Saturday during a clash with police in Kandahar province, Stanizai said.