A pair of suicide bombers disguised as policemen have attacked a government compound in northwestern Pakistan. At least 50 people have been killed.

The explosions, also wounded more than 100 people, many critically. The blast took place in one of Pakistan's semi-autonomous tribal areas, while a tribal jirga was meeting to discuss forming an anti-Taliban militia.

The attack was the latest to target local tribesmen who have been encouraged by the government to take up arms against the Taliban.

A local official says the dead and wounded included tribal elders, police and politicians.