Police spokesman Ajith Rohana said an initial investigation showed the negligence of the driver caused the accident. It wasn't immediately clear if the driver survived.
Earlier on Saturday state news agency PAP reported that the bus, with 57 people on board, fell into a ditch at night. The injured were taken to local hospitals and the remaining passengers were brought to a local school.
A bus collided head-on with a truck in southern India state of Tamil Nadu on Thursday, killing at least 20 people and injuring 23 others, police said. Twelve victims who were travelling on the ill-fated state-owned luxury have been identified, said a Kerala police official.
Iraqi politicians called for an investigation, saying the passengers were Shiite pilgrims on their way to visit shrines in Damascus, which has been largely protected from the ongoing war. But such convoys have previously come under attack from armed groups.
The cause of the accident was unclear, and rescue workers were still working at the scene recovering the injured and the dead and taking them to a nearby hospital, said Faiz Ullah Faraq, spokesman for the Gilgit-Baltistan region.
The bus crashed into a guardrail and veered into Hongshan Lake in Guizhou province, leaving 15 others injured.
The nearly 40 passengers on the bus were classmates from Dong Hoi High School who were travelling to visit the area in central Quang Binh province for the 30th anniversary of their graduation.
At least 33 passengers, mostly laboureres, travelling home to celebrate Eid Al Adha with loved ones, were killed and over 40 others injured when their bus rammed into a truck on a highway in central Pakistan on Monday.
The accident occurred overnight in Barabanki, 30 kilometres (18.6 miles) northeast of Lucknow, the capital of Uttar Pradesh state. According to the Ram Sanehighat police circle reports, the mishap took place in the early hours of Wednesday.