An explosive-laden vehicle has rammed into a convoy in northwestern Pakistan, causing a blast that has killed five Chinese engineers and one Pakistani driver.

The explosion occurred on Tuesday on a major road in a mountainous area of the Khyber Pakhtunkhwa province. The convoy was heading for a dam construction site.

Police said the convoy was carrying engineers and security workers involved in the dam project. They explained that one vehicle fell into a gorge after the blast, causing the six deaths.

The police believe this is a suicide bombing targeting Chinese construction personnel. They say a man who is believed to be the attacker also died.

Pakistan has seen a series of attacks believed to have been carried out by armed groups disgruntled with China.

An armed group stormed a port facility in Gwadar in southwestern Pakistan last Wednesday. The site is known as a key base for the China-led Belt and Road initiative.