More than 100 passengers aboard a boat have been stranded since late Wednesday after thick fog forced the Three Gorges Dam ship lock to close.

An official of the Changjiang Three Gorges Navigation Administrative Bureau said they had fully explained the reason for the closure and asked the passengers to remain calm.

He said a thick fog, the first this spring, engulfed the Three Gorges Dam area at 4:44 p.m. on Wednesday, and the channel for southbound vessels was the first to close as visibility at Huangling Temple downstream was less than 500 meters.

The northern way was also forced to close around 5:10 p.m. as visibility around Xianren Bridge upstream fell below 500 meters.

Twenty-five ships were navigating at the ship lock when the closures began on Wednesday. By 9 a.m. Thursday, 13 cargo ships and one passenger vessel were still inside the five-tier ship lock.

Thick fog has also affected Gezhouba, which sits downstream of the Three Gorges Project. Its lock is also closed.

"We hope the fog will disperse soon so that we can resume services and reopen navigation for the vessels stuck at the Three Gorges Dam area," said the official.

(Xinhua News Agency, March 13, 2008)