Six Pakistani troops including a senior army officer were killed Friday when a roadside bomb hit their vehicle in a northwest tribal region near the border with Afghanistan, local sources said.

Another two soldiers were injured in the blast in upper Orakzai tribal area on their way to nearby Kohat, a main city in the area, they said.

The deceased senior Pakistani military officer was identified as Colonel Yousuf. The vehicle was completely destroyed in the incident at Yakh Kandaou area.

Rescue efforts have been underway and the injured were shifted to hospital in Kohat.

No group claimed responsibility for the attack. The security forces launched a search operation after the attack. Orakzai agency is a stronghold of Taliban militants and they regularly target the security forces and pro-government tribal elders.

Roadside blasts are a common strategy adopted by militants in the troubled northwest against military operations trying to wipe the area clean of insurgency.

However on Thursday, six militants were killed including a local commander when their vehicle ran over a landmine which probably was planted by other groups on roadside in Kurram agency.

In another similar incident on Wednesday, six troops were killed and their military vehicle was destroyed in a landmine blast in Kurram.