A race car veered off the track and crashed into a crowd of spectators and race officials during an event in the town of Diyatalawa, Sri Lanka, on Sunday, killing seven people and injuring 20 others, officials told Bharatha Mallawarachi of the Associated Press.

The cause of the crash remains unclear. The report noted that 45,000 spectators were in attendance at the race circuit at a Sri Lankan military academy for the Fox Hill Supercross event, which was organized by the Sri Lankan army and Sri Lanka Automobile Sports.

Police spokesman Nihal Thalduwa said four officials were among the seven killed when the race car crashed into the crowd. He added that of the 20 being treated at the hospital, three were in critical condition.

The race was suspended following the accident, which occurred during the 17th out of 24 events scheduled. Thalduwa said police have opened an investigation into the crash.

Diyatalawa is located about 110 miles east of the Sri Lankan capital city of Colombo.