Watch: Bus carrying construction workers in Pakistan falls into a ravine killing at least 13 people

13 people have died, including nine Chinese nationals, after a bus carrying construction workers fell into a ravine in Pakistan on Wednesday, officials have confirmed.

It came after overnight rain caused the road in Kohistan to become wet, but the exact cause of the incident, which also injured at least 36 people, remains unknown.

In a statement, the Chinese Embassy said the bus was attacked, but a Pakistani government spokesman has asked the media not to speculate, with officials still investigating the crash.

They added that a briefing from investigators would be given to the press soon.