Four people were killed and another four were injured after the tractor they were taking collided with a truck early Friday morning in east China\'s Anhui province, local authorities said. The accident happened at 3:50 a.m. in Dingyuan county but it is so far unclear how the collision occurred. The eight were all passengers on board the tractor from Hongxin township of Fengyang county. The truck is owned by a transport company in the city of Huainan.