At least four killed as Pakistani Taliban militants storm police HQ in Karachi

Officials say three attackers also dead as police and paramilitary forces clear building in gun battle

Militants launched a deadly suicide attack on the police headquarters of Pakistan's largest city on Friday, with the sound of gunfire and explosions rocking the heart of Karachi for several hours.

Two police officers, a ranger and a civilian were killed and 14 others wounded, said Murtaza Wahab, a government spokesman in Sindh province, where Karachi is located. Two suicide bombers were killed and at least one blew himself up after entering the police building, officials said.