KUNDUZ, Afghanistan (Reuters) -- Taliban fighters stormed a district police headquarters in once-quiet northern Afghanistan overnight, killing the police chief and two of his men, an official said, as violence spreads into once safe areas.
The attack, which led to a four-hour gunbattle into the early hours of August 12 in Kunduz, is the latest in a wave of rising violence a week before an August 20 election which militants have vowed to disrupt.
The attackers struck with small-arms fire and rocket-propelled grenades under cover of darkness, said Sheikh Saduddin, administrator of the Dasht-e-Archi district of Kunduz Province.
The province, north of the Hindu Kush mountains and far from the southern war zone, has been largely quiet since Taliban militants were driven from power in 2001, but has seen escalating attacks in recent months.
This week the overall commander of NATO and U.S. troops in Afghanistan said militants were advancing from their traditional bastions in the south and east into previously quieter areas in the north and west.
After several hours of fighting, the militants abandoned the building following police reinforcement, Saduddin said.
"They [Taliban] killed the police chief and two other officers. Three more police were wounded," he said, giving no information about Taliban casualties.
Violence in Afghanistan, at its worst since U.S. and Afghan forces overthrew the Taliban in 2001, has increased further ahead of the election.
The United States has sent tens of thousands of extra troops to Afghanistan this year, where the Western force now numbers more than 100,000 for the first time, including 62,000 Americans.
President Hamid Karzai said on August 11 the militants would not be able to disrupt the vote.