BEIJING - Liaodong Bay in northeast China's Bohai Sea on Wednesday has been partly frozen, according to the National Marine Environmental Forecasting Center.

Ice covers about 7 sea miles in the bay, the earliest date that sea ice had appeared in the area in 10 years, according to the center.

The acreage of sea ice in Bohai Sea will rise to 10 to 12 sea miles with an average thickness of 5 cm in the following week due to dropping temperatures.

Ice also covered the shallow estuaries in the north of the Yellow Sea, also the earliest in 10 years.

The center urged departments along the coasts of Bohai and north Yellow Sea to take precautions against damage to ships and facilities.

Also on Wednesday, the center forecast huge waves in the East China Sea, around the Diaoyu Islands, the Taiwan Strait and northeast part of South China Sea from Wednesday night to Thursday, issuing a blue alert.