Seven people are still missing Monday after a fishing boat with 11 crew aboard capsized and sank in Xijiang River in South China's Guangdong Province early on Sunday.

Local government and maritime authorities in Yunan county have barred other vessels from entering the area where the boat sank, and have dispatched rescue boats and frogmen to search for the missing people, according to a statement issued Monday by the Guangdong Maritime Affairs Bureau.

To date, no sign of the missing people has been found, the statement said.

Four of the boat's crew had been rescued after the accident.

How the boat capsized and sank remained unknown, although collision has been ruled out, it added.