More than 2,000 vessels were stopped Friday by thick fog at the mouth of the Pearl River in south China's Guangdong Province, said local maritime authorities.

The vessels were stopped for safety concerns as the visibility was less than 200 meters, said a spokesman with the marine safety administration of Guangzhou, the provincial capital.

The dense fog was caused by cold air that has swept Guangdong since early March, the spokesman said.

It remained unclear when vessel traffic would resume, he said.

Source: Xinhua