KABUL, Afghanistan - Taliban fighters wearing suicide-bomb vests under police uniforms attacked a government building Sunday in eastern Afghanistan, triggering an hours-long gun battle and killing six people, officials said.

Taliban spokesman Zabiullah Mujahid claimed responsibility for the attack in Khost province. It came a day after a Taliban suicide bomber slipped inside the capital's main military hospital and killed at least six medical students - reminders of the militants' ability to infiltrate sites thought to be secure.

In the attack Sunday, just before dawn, four men armed with assault rifles and wearing explosives drove into a compound that houses the provincial traffic department on the edge of Khost city, said Gen. Abdul Hakim Ishaqzai, the provincial police chief. Security forces stopped the men, who were wearing border-police uniforms, after becoming suspicious of the civilian station wagon they drove, he said.

Guards opened fire on the attackers, but the men were able to occupy the upper floor of the building. The attackers shot at Afghan security forces from their vantage point as a fire raged through the structure. AP Television News video showed U.S. soldiers surrounding an outer wall and shouting orders as Afghan troops rushed toward the building, which was engulfed in smoke.

Two of the attackers detonated their bomb vests during the fighting, with one bomber killing two Afghan soldiers, said Gen. Raz Mohammad Oryakhail. Security forces shot and killed the other two attackers. Three police officers and a gardener were also killed, Ishaqzai said. Five police officers, a soldier, and a civilian were wounded.