QUETTA, Pakistan — A speeding passenger bus fell from a highway into a rocky ravine in southwest Pakistan early Wednesday, killing 28 people and injuring 20 others, officials said.

Local police officer Asghar Ali said the driver lost control suddenly in Washuk town as the bus was traveling from Turbat, the second-largest city in Baluchistan province, to Quetta, the province’s capital. Police were trying to collect details from the injured.

Ismail Mengal, a government administrator in Washuk, said the driver of the bus was among the dead. He said officers are still trying to determine the cause of the crash.

He said rescuers and police quickly responded and provided initial medical treatment to the injured passengers. Police transported the dead and injured to a hospital, where some of the injured were in critical condition.

Local media pictures showed the wreckage at the bottom of a rocky ravine.

In a statement, Sarfraz Bugti, the chief minister in Baluchistan, expressed grief over the loss of lives, and he ordered the best possible medical treatment be provided to the injured.

Prime Minister Shehbaz Sharif and Interior Minister Mohsin Naqvi in separate statements expressed sorrow over the deaths.

Road accidents are common in Pakistan where traffic rules and safety standards are sparsely followed, even on battered roads in particularly rugged areas.

The latest accident occurred three days after 13 members of a family were killed in a deadly collision between a van and a truck in Multan, a city in the eastern Punjab province.

At least 20 people were killed and another 30 were injured earlier this month in a similar crash.