The general cargo ship Xiang Zhou sank at the Yangtze River estuary off Nantong after a collision.
The Maritime Herald website says the nearby ships saw the accident and succeeded to rescue two seamen.
The accident was reported to local authorities and a large scale-search and rescue operations wa launched for the missing sailors, who are feared to have been trapped.
The ship was on a voyage from South Korea.
Photo: Vessel Tracker.com Kiribati-flagged cargo ship Xiang Zhou