Suicide car bombers killed 16 people and wounded more than 80 in two attacks in northwestern Pakistan on Friday, including a devastating strike on the regional headquarters of the spy agency overseeing much of the country's anti-terror campaign.

The bombings were the latest in a string of attacks on security forces, civilians and Western targets since the government launched an offensive in mid-October against militants in the border region of South Waziristan, where al-Qaida and Taliban leaders are believed to be hiding out.

The attack on the Inter-Services Intelligence agency building occurred in the city of Peshawar, which has borne the brunt of the militants' retaliation against the army offensive. A wave of bombings in the last week alone in and around the city has killed more than 50 people.

Security forces guarding the intelligence complex opened fire on a pickup laden with explosives, but the bomber was able to detonate his payload, said an intelligence official, speaking on condition of anonymity because he was not authorized to talk to the media.

'Guerrilla war'
The early morning blast, heard across the city, destroyed much of the three-story building and killed 10 people, including seven who worked for the spy agency, the army said in a statement. Another 55 people were wounded, officials said.

"This is a guerrilla war," said Mian Iftikhar Hussain, the information minister for North West Frontier Province, where Peshawar is the capital. "We will continue our action against these militant terrorists. That is the only way we can survive."