Islamabad: Three policemen, including a deputy superintendent, were killed on Friday when a roadside bomb blew their vehicle up in northwest Pakistan.

The improvised explosive device believed to have been planted by militants hit the vehicle in Lakki Marwat district, said police officer Romali Akram.

Deputy Superintendent Javed Iqbal and his driver and guard were killed and three were injured, one of them critically, Akram said.

"It was a terrorist act meant to create terror among local people," he said.

The district borders on tribal Waziristan region, a hub of Taliban and Al Qaida linked militants blamed for a number of recent attacks on security personnel in the area.

Two weeks ago three employees of the atomic energy commission were kidnapped from Lakki Marwat and they still remain untraced.

On Thursday, a missile destroyed a house in South Waziristan, killing up to a dozen suspected militants, including some Arabs and Turken, reports said.

The military said information indicated the explosives stored in the house resulted in the blast.

Residents and reports said the missile was fired from a drone belonging to Nato forces stationed in neighbouring Afghanistan.