Seven people have been killed after a pickup truck crashed head-on into a sedan in northeast China's Heilongjiang Province, local government said on Sunday.

The truck, carrying three people, ran into an oncoming Hongqi car after being hit by another passenger vehicle Saturday noon in Boli County, said Wang Xiaowei, an official with the county's traffic police brigade.

The three inside the truck were killed on the spot, Wang said.

Also, four people in the Hongqi were killed after it burst into flames, he said.

The driver of the other passenger vehicle, who was left unhurt, has been detained.

An investigation is underway into the cause of the tragedy.