Pakistani security forces have killed at least 40 militants in the country’s troubled northwestern tribal region close to the border with Afghanistan.

The causalities come after Pakistani troops opened heavy fire on militant hideouts in Wana, the main town of South Waziristan tribal region Press TV reported.

Military sources say four soldiers also lost their lives during the hours-long offensive.

The clashes broke out after militants abducted and killed two security officials in the troubled region on Sunday.

Militancy is rampant in the several tribal districts of Pakistan close to the Afghan border.

Militants have carried out numerous attacks on security forces as well as civilians and managed to spread their influence in various regions of the country, despite frequent offensives by the Pakistani army.

More than 35,000 Pakistanis have lost their lives in bombings and other militant attacks since 2001 when Pakistan joined an alliance with the US on the so-called war on terror.

Thousands more have been displaced by the wave of violence and militancy sweeping across the country.