A car bomb ripped through a police compound in a northwestern Pakistani city, of Peshawar killing 18 people, including 14 women and children and four officers, the latest in a string of attacks proving that Islamist militants remain a potent force in the country.

Khalid Omarzai, the city's top government official, said the civilians killed were the wives and children of police officers.

He said another 94 people were wounded in Tuesday's bombing, adding that they had been taken to hospitals after rescuers cleared rubble of over two dozen collapsed houses and shops.

Kohat, the major town on the road between the provincial capital of Peshawar and several tribal areas, has been the scene of several militant attacks this year.

Meanwhile, intelligence officials say a suspected US missile strike has killed at least four militants in northwestern Pakistan near the Afghan border, AP said.

The officials say Wednesday's drone strike targeted a house in the village of Dande Darpa Khel in the North Waziristan tribal area.

They spoke on condition of anonymity because they were not authorised to talk to the media.

The area targeted by strike is a stronghold of Hafiz Gul Bahadur, a militant leader who concentrates his attacks against Nato forces in Afghanistan.

The US refuses to publicly discuss drone missile strikes in Pakistan, but officials have said privately that they have killed several senior Taliban and Al Qaida militants.