In the early hours of Sunday, May 11, a passenger bus veered off the road and plunged into a ravine near Kotmale, a village in a mountainous region of south-central Sri Lanka, according to police report.

Initially, Sri Lankan authorities reported that 8 people, five men and three women, had died, and over 30 people, including the bus driver, were seriously  injured and taken to nearby hospitals for treatment. At the time, the identities of the deceased had not yet been confirmed.

A police spokesperson later shared an updated death toll with Associated Press, revealing that the death toll had nearly tripled.

Policelice spokesman, Buddhika Manathunga, says 21 people died and 35 were injured in the bus accident, the AP reported.

The vehicle is owned by a state-run bus company and traveling from the town of Kataragama to the city of Kurunegala, police said.

As the injured continue to receive treatment, police are investigating to determine the cause of the accident, as it is not immediately clear whether a technical issue, the driver or something else led to the fatal accident, the AP reported.

Images of the aftermath of the accident how ever shows that the roof of the bus separated from the rest of the vehicle, which rests at a diagonal on the side of a hill, per the AP. Several seats on the bus appear to have detached from the bus, whose contents strewn about the ravine where it landed.