Four people are missing after a passenger boat capsized Friday in the Songhua River in northeast China's Heilongjiang Province, local authorities said.

Eight people, including the boat owner, a couple, were aboard the 12-seat boat when the accident occurred at about 7:40 a.m. on a section of the river in Harbin, the provincial capital, the city's work safety department said in a statement.

The boat lost power due to engine failure about 100 meters from a floating bridge. It overturned after crashing into the bridge, it said.

All eight people fell into the river water, but four were saved after staff at the bridge administration station threw life buoys into the water.

Six people, including five men and a woman who were former classmates, rented the boat for a tour on the river.

A search has begun for the four people who disappeared in the wide, fast-flowing waters and strong winds.

The statement gave no further details.