A suicide car bomber targeted NATO forces on Monday outside the major southern Afghan city of Kandahar, killing four civilians, the Interior Ministry said. It was not immediately known if there were any NATO casualties.
The attacker waited in a station-wagon taxi near a bridge between the airport and city that NATO troops regularly check for explosives, said Inhamullah Khan, an Afghan army official at the bombing site.
The assailant detonated the bomb as the convoy crossed the bridge in the morning, tossing a military vehicle into the ravine below, Mr Khan said.
Mr Khan did not have information on NATO casualties. NATO spokesman Maj. Marcin Walczak of the Polish Army said the international military coalition was aware of the incident but did not yet have any details on casualties.
The Interior Ministry confirmed four civilian deaths in a statement. Three of the civilians who died were in a car that had pulled over nearby to wait for the convoy to pass, Mr Khan said.
Kandahar city, the capital of the province of the same name, is east of Helmand province, where thousands of U.S., NATO and Afghan troops are conducting a two-week old offensive to wrest control of the town of Marjah.
The town has long been controlled by the Taliban and the assault is seen as the first step in a multi-month offensive that will eventually target Taliban strongholds around Kandahar city.