At least two people were killed and 22 others injured when a suicide bomber rammed a vehicle laden with explosives against a convoy of the security forces in Pakistan's restive northwest region on Thursday, police said.

The incident happened in the Dera Ismail Khan district of the country's Khyber Pakhtunkhwa province when the security convoy was on the move from one part of the district to another.

"In the suicide blast, at least 2 people were killed and 22 others injured. The two deceased are believed to be from the Army. However, it is not confirmed yet," said a senior police officer.

The injured have been shifted immediately to a nearby hospital.

The security forces and the police have rushed to the site and blocked the main Tank-Dera Ismail Khan road for all kinds of traffic.

An official of the Bomb Disposal Squad said "we are determining the quantity of the explosives used in the suicide hit".

The Khyber Pakhtunkhwa province is a very restive state and attacks on security forces occur very often.

Last week, an armed group attacked a military post in northwestern Pakistan near the border with Afghanistan using a vehicle laden with explosives as well as suicide bombs, killing seven security force members.

In December last year, a total of 23 soldiers were killed when militants linked to a Pakistani Taliban affiliate rammed an explosive-laden vehicle into a security forces' post in Khyber Pakhtunkhwa province.

Except for the headline, this story has not been edited by The Telegraph Online staff and has been published from a syndicated feed.