JINAN - Five people were killed, and another five injured after a truck-tractor slammed into a passenger bus Monday morning in eastern Shandong province, local authorities said.

The accident happened around 5:40 am in the province's Yangxin county, according to the county's public security bureau.

Two people died on the spot, and eight were injured and sent to hospital, where three of them died, the bureau said.

An investigation into the cause of the accident is under way.