The bus carrying about 35 passengers fell into a deep ravine in Balochistan province; 12 others were wounded.
A passenger bus slid off a mountain road and fell into a deep ravine in heavy rain in southwest Pakistan on Sunday, killing 19 people and injuring 12 others, a government official said.
Mahtab Shah, the assistant administrator for the district of Shirani in Balochistan province, said about 35 passengers were on the bus, travelling from the capital Islamabad to Quetta city.
The death toll is expected to rise since many of those injured were in critical condition.
He said rescue workers were searching for survivors in the wreckage of the destroyed vehicle and surroundings that borders Khyber Pakhtunkhwa province.
Shah said apparently the bus slid on the wet road amid heavy rain and the driver lost control of the vehicle, which fell about 200 feet (61 metres) into the ravine.
At least 22 people died when a minibus plunged into a ravine in Balochistan last month.