At least 31 children and four adults were killed when a bus crashed on the motorway southeast of Pakistan's capital Islamabad, officials said Tuesday.
The bus, which was ferrying private school pupils back from a picnic, came off the road and fell into a ravine in Punjab province late Monday.
"Thirty-five people, including 31 children and four adults, have been killed in the accident," Naseem Sadiq, a senior administration official in the children's home district of Faisalabad, told AFP.
"The driver, his helper, vice principal and a teacher of the school were also among the dead," he said.
"All the children were aged 10 to 15," said Doctor Sultan Alamgirian, head of Chakwal's main district hospital, where the dead and injured were evacuated.
Speaking from the scene of the crash in Chakwal, about 100 kilometres (60 miles) southeast of the capital, senior police officer Chaudhry Salim said overnight that 24 school students were among at least 30 dead.
Officials said they would investigate the cause of the accident, but said early reports indicated that the brakes failed.
In June, at least 12 children were killed and two others wounded when their school bus plunged into a canal in Pakistan-administered Kashmir.
Pakistan has one of the world's worst records for deadly traffic accidents, blamed on poor roads, badly maintained vehicles and reckless driving.