The bold afternoon raid showed insurgents are still able to launch deadly strikes on heavily fortified government institutions despite the past year's influx of US troops into Kandahar province, the Taliban's birthplace. The Taliban claimed responsibility for the attack.
Fifteen of those killed were Afghan police officers, said provincial Governor Toryalai Wesa. Interior Ministry spokesman Zemeri Bashary said three Afghan soldiers, two civilians and one intelligence service agent also died in the assault.
Insurgents first struck around noon, detonating a series of explosions that rocked the area near the provincial police headquarters. The police post is located in central Kandahar, not far from the governor's offices.
Initial reports suggest a car bomb exploded outside the police compound, and then immediately afterward two suicide bombers tried to storm the headquarters but blew themselves up outside the perimeter wall, according to NATO officials in Kandahar.
Five militants fitted with suicide vests battled with police for several hours, Bashary said. Some occupied a multistory building housing a wedding hall across the street from the headquarters. From there, they fired on the police headquarters compound with automatic rifles and rocket-propelled grenades.
An Associated Press reporter nearby said multiple explosions rocked the neighbourhood around the station. Exchanges of gunfire occasionally died down, only to pick up again several minutes later.
Residents quickly shuttered shops and took cover inside as the fighting raged, and NATO vehicles could be seen inside the city. Helicopters hovered over the city as police deployed extra forces on the streets and around government buildings. Several loud explosions again rattled buildings more than an hour after the first blast struck.