Bulgarian authorities say that a passenger bus flipped over on a highway near the capital, Sofia, killing at least six people and leaving 22 others injured, including one child.

Police said that the accident occurred on Monday after a car crashed into the bus. The bus driver then lost control of the vehicle and the bus overturned into a roadside ditch.

The driver of the car was taken into custody for questioning.

The accident happened at 11.30 a.m. local time on Friday, some 25 kilometer (15 miles) east of the capital, Sofia. The bus was carrying passengers from the Black Sea town of Burgas to Sofia.

Ambulances took the injured to Sofia hospitals. Doctors said that seven of them were in critical condition.