At least five people were killed in two traffic collisions triggered by thick fog on expressways in east Anhui province Monday, local authorities said.

A truck collided with a bus at about 2:30 a.m. on an expressway in Huaiyuan county, killing three people, local traffic police said.

Six vehicles collided at noon on an expressway near Jieshou city, killing at least two people and injuring an unknown number of others, according to local traffic police. A rescue operation is under way.