A bus accident in Pakistan's northwestern valley of Swat left 16 people dead, including 10 children, officials say.

The bus, carrying passengers home from the central Punjab province to the Kalam hill station in Swat district, crashed on the roadside close to a river on Tuesday morning.

"Sixteen people have been killed in the accident including 10 children and five women. Seven other passengers have been injured," AFP news agency quoted Mehmood Asalam, a senior administration official in Swat, as saying.

"We don't know any reason for the accident at the moment. It may have been caused because driver slept while driving."

Shakeel Khan, local police official, confirmed the death toll, and said that the injured had been taken to a local hospital.

"The injured included three men, as many women and a child," Khan said.

Pakistan has one of the world's worst records for fatal traffic accidents, blamed on poor roads, badly maintained vehicles and reckless driving.

In April, a bus collided with a tractor in Sind province, killing 42 people and in January, 20 people including 17 children were killed in a crash, also in Sindh.

Source: Agencies