At least 14 passengers were killed and 63 others injured when a speeding passenger bus crashed off a motorway and overturned in eastern Pakistan, police and government officials said Monday.

The overnight crash happened near the town of Kallar Kahar in Punjab province, a deputy commissioner, Quratulain Malik, said. She added all the dead and injured had been moved to a hospital.

She provided no further details and police said they were still investigating the cause.

Prime Minister Shahbaz Sharif in a statement expressed his grief and sorrow over the loss of lives in the crash and ordered authorities to provide the best possible medical treatment to the injured.

Last month, a passenger bus crashed into a pillar and fell off a bridge, catching fire and killing 40 people in the southern district of Lasbela.

Traffic accidents in Pakistan generally happen due to violations of traffic rules, resulting in the deaths of thousands every year.