About 110 children were on board the bus which was only certified to carry 70 passengers [EPA]

At least 37 people, including 30 children, have died after a bus overturned on a motorway in the Punjab province in Pakistan.

The vehicle, carrying more than 100 children, had been travelling back from Kalar Khar, when the accident happened on Tuesday.

Local media reported three teachers, the school's principal and the bus driver were also killed.

Distraught parents waited anxiously for news of their children.

Forty-five students, mainly between the ages of 12 and 13, had minor injuries, and up to 30 sustained serious injuries.

One student told reporters that the principal had asked the driver to slow down when he realised the brakes had failed.

The driver reportedly asked students to pray just before the accident happened as he made a sharp turn.

A local official said the bus, which had 110 people onboard, was only certified to carry 70.

Source: Agencies