Over 100 flights were canceled and 100 others delayed Thursday as heavy fog covered an airport in northeast China's Liaoning Province, said airport workers Thursday.

Planes could neither land nor take off at Zhoushuizi International Airport at coastal city of Dalian, an airport employee told Xinhua over the phone.

Visibility has dropped to less than 200 meters as heavy fog engulfed the city beginning Wednesday.

But the airport employee did not disclose how many passengers were stranded at the airport.

Fog was becoming heavier as night falls, said a Xinhua reporter on the scene.