An overcrowded bus carrying dozens of Buddhist pilgrims plunged off a cliff in central Sri Lanka early Sunday, killing at least 21 people and injuring 24 others, officials said.

The island nation's winding roads are among the most dangerous in the world, and the crash off a cliffside road in central Sri Lanka was among the deadliest recorded in decades.

Photos of the wreckage showed that the roof and side panels of the bus were sheared off, and more than half of the seats were ripped from the floor of the vehicle, which landed upside down in a tea plantation.

The state-owned bus was carrying around 70 passengers — about 20 more than its capacity — through the hilly region of Kotmale when the driver lost control and it veered off the road before dawn, police said.

"We are trying to establish whether it was a mechanical failure or if the driver fell asleep at the wheel," a local police official told AFP, speaking on condition of anonymity because he was not authorized to speak to media.

Deputy Transport Minister Prasanna Gunasena told reporters at the scene that the injured were rushed to two area hospitals.

"Twenty-one have died and we are trying to identify the victims," Gunasena said.

The toll could have been higher, the minister added, if not for local residents who helped pull people from the mangled wreckage and rushed them to hospitals.

Police confirmed that 24 people were being treated in the two hospitals.

One survivor told a local journalist that he had been in the front section of the bus and was lucky to escape with only minor injuries.

"The bus was leaning to the left side and as the driver was negotiating a bend, he lost control and it fell down the precipice," said the man, who did not give his name, in a video seen by AFP.

The bus was traveling from the pilgrim town of Kataragama in the island's deep south to the central city of Kurunegala, a distance of about 250 kilometers (155 miles).

Sri Lanka records an average of 3,000 road fatalities annually, making its roads among the most deadly in the world.

Sunday's crash was one of the worst since April 2005, when a bus driver attempted to beat a train at a level crossing in the town of Polgahawela. The driver survived with minor injuries, but 37 passengers were killed.

In March 2021, 13 passengers and the driver of a privately owned bus died when the vehicle plunged into a precipice in Passara, about 100 kilometers east of Sunday’s crash site.