Four suicide bombers blew themselves up and gunbattles broke out in southeastern Afghanistan after militants tried to storm provincial government buildings on Tuesday, Afghan officials said.
The attack in Khost town follows similar raids in other towns in recent months, a sign of the violence that Taliban militants have vowed to step up as more U.S. troops deploy to the country over the next few months.
The suicide blasts killed at least six people -- four army soldiers and two civilians -- and wounded 13, said Hamid Padshah, a doctor from a hospital in Khost, adding the toll may climb.
State television said security forces had surrounded the municipal administrative building with Taliban fighters inside. The building was on fire following a series of explosions, several officials who asked not to be identified said.
Interior ministry spokesman Zemaray Bashary said one suicide bomber was killed by police as he tried to break through the gate of the headquarters of Khost's governor in a vehicle.
Explosives in his car went off and killed the soldiers, he said. In another part of town, the other three suicide bombers clashed with security forces and their explosive vests were detonated, Bashary told state television.
A spokesman for a NATO force with troops in the town said four suicide bombers had blown themselves up but gave no further details.
Despite reinforcements to foreign forces in Afghanistan, violence has surged in the past year, making it the bloodiest period since U.S.-led troops overthrew the Taliban government in 2001.
The latest attacks are similar to high-profile strikes by militants in other parts of Afghanistan in recent months, including in the capital Kabul.
Khost is near the porous Pakistani border and separated by mountains from other parts of Afghanistan.
The spread of Taliban attacks in Afghanistan and neighbouring nuclear-armed Pakistan has raised alarm worldwide.
The new U.S. administration is sending 17,000 soldiers to Afghanistan in the next few months, part of a wave of reinforcements that will see the total US force increase from 32,000 at the start of this year to 68,000 by the year's end.