ZHENGZHOU - Six people were killed and 35 others injured on Monday in a series of pileups that were caused by heavy fog in Central China's Henan province, authorities said Tuesday.

The accidents occurred between 7 and 8 am Monday on an expressway that links Northeast and South China, the Henan Public Security Department said.

The accidents were blamed on low visibility caused by the heavy fog. One of the accidents involved more than 10 vehicles, traffic officers said.

Three people died on the spot, while another three died after being taken to hospital.

All of the injured have been sent to two nearby hospitals. Their condition is not yet known.

Traffic on the expressway had resumed by noon Monday. An investigation into the accidents is under way.