A homicide bomber killed seven people outside a NATO base in southeastern Afghanistan Wednesday, a local official told Reuters.

Twenty-one more civilians were wounded when the bomber’s car exploded outside the gate of the NATO base in Afghanistan’s Khost town.

The attack comes just one day after a group of Taliban homicide bombers attacked government buildings in the same town, killing at least 20 people.

Violence in Afghanistan has increased to its worst level since the U.S.-backed Afghan forces overthrew the Taliban in 2001, even as the number of foreign troops in the country has surged.

An official from the province said all the victims of the attack were workers at the NATO base.

"U.S. forces ... have encircled the area," provincial official Wazir Padshah told Reuters. "The toll may rise."

There are no reports of injuries or casualties among NATO-led troops.

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