Islamabad, Sep 24 (DPA) Suspected Islamist militants targeted a group of pro-government tribesmen near Pakistan's northwestern Bannu town Thursday, triggering a gunfight that left at least 18 people dead, police and intelligence officials said.

Gunmen ambushed two vehicles carrying members of a tribal militia, including a few prominent chieftains, as they travelled through the Janikhel area bordering the country's lawless tribal region.

'Six militiamen and a passer-by were killed after militants opened indiscriminate fire from different directions,' Bannu police chief Iqbal Marwat told DPA by phone. Tribal chieftain Malik Sultan was among the dead.

Six more people, mostly pedestrians, were wounded in the assault, according to Marwat.

A second round of violence came when surviving militiamen came under attack as they tried to recover the bodies and the injured. Tribesmen returned fire with the help of the locals and were later joined by the security forces.

The ensuing clash killed six assailants, three civilians and two militiamen, an intelligence official in the area said on condition of anonymity.

Local tribes had formed a militia in recent months to aid the government in purging their area of Taliban rebels.

Janikhel borders Pakistan's troubled North Waziristan tribal district, a known hotbed of Al Qaeda and Taliban fighters, who use the territory to plan and carry out attacks on the Western troops in neighbouring Afghanistan.