At least 10 people were killed in a collision between a passenger bus and tractor-trolley in Punjab's Layyah district early Wednesday, police said.

As many as 23 people were also injured when the Rawalpindi-bound bus collided with a tractor-trolley on Layyah's Karor road as a result of over-speeding, the police official said. The bus was carrying passengers from Karachi.

Women and children are among the 10 people killed in the accident.

The injured were shifted to nearby hospitals soon after the incident, while four passengers were shifted to Multan's Nishtar Hospital in a critical condition.

Eyewitnesses told DawnNews that some passengers were also travelling on the roof of the bus.

In Pakistan, around 9,000 road accidents are reported to the police every year since 2011, killing more than 4,500 people on average, according to figures from the Pakistan Bureau of Statistics (PBS).