A race car veered off the track during a competition in Sri Lanka on Sunday and rammed into a crowd of spectators and race officials, killing seven people and injuring 20 others, officials said, Paralel.Az reports citing AP.

Thousands of spectators looked on as the mishap took place during a race in the town of Diyatalawa in the tea-growing central hills, about 180 kilometers (110 miles) east of the capital Colombo.

It wasn’t immediately clear what caused the mishap.

Police spokesman Nihal Thalduwa said one of the cars veered off the track and crashed into spectators and officials of the event. Seven people, including four officials, were killed and another 20 were being treated at a hospital, said Thalduwa. He said three of the injured were in critical condition.

Thalduwa said police have launched an investigation into the accident, which was the 17th out of 24 events scheduled. The race was suspended after the accident.