GUANGZHOU - Six people were rescued and five remain missing after a merchant ship sank off the coast of south China's Guangdong province on Monday, according to rescuers.

The ship, code-named Sheng'anda7, sank in the early morning after colliding with another merchant vessel in the waters off Dong'ao Island in the Pearl River estuary, said a statement from the provincial maritime search and rescue center, which received an SOS at 6:30 a.m.

Eleven crew members aboard Sheng'anda7 fell into the water, and six of them had been saved by 10 a.m., said the statement.

Four rescue ships, four helicopters and several nearby vessels are searching for the missing, it said.