Four people were killed and several others injured Sunday when a driver competing in a Hungarian motorsport rally skidded off the road and crashed into spectators, authorities said.

According to a police statement, it is not yet clear why the vehicle taking part in the two-day Esztergom Nyerges Rally in northern Hungary veered off the road.

The crash occurred between the towns of Labatlan and Bajot in the northern Komarom Esztergom county, and left at least four people dead and seven injured, police said, adding that an investigation is underway.

Several ambulances and rescue helicopters were dispatched to the scene, and the rally was immediately halted.