Afghan police backed up by U.S. troops killed two gunmen who detonated a bomb in the eastern city of Khost on Monday and then holed up in an unused police building, an official said.

The attackers were the only people to die in the shootout, but one police officer and an Afghan army soldier were wounded, said provincial Gov. Taher Khan Saberi.

Acting chief of police in Khost, Yaqob Khan, said the attackers set off an explosion, then stormed into a building next to a police station. Officers and troops surrounded the attackers and fired on them with automatic weapons and rocket-propelled grenades as the gunmen returned fire, Khan said, adding that U.S. troops from a nearby base rushed to the scene to assist.

Officials all referred to the men as suicide attackers, indicating they meant to die in the second round of explosions.

The attackers — who appeared to follow recent insurgent pattern of an explosion followed by attackers storming a building — appeared to have mistakenly targeted an abandoned building, Khan said. He said the intended target may have been the police station next door.

Saberi said the building that was targeted was actually owned by police but was empty.