HEFEI - One more person was confirmed missing after a ferry sank in east China's Anhui Province on Thursday, bringing the number of missing people from 12 to 13, local authorities said Saturday.

About 400 rescuers and 37 vessels were still searching for the missing people in an area of 42 square kilometers in the Ma'anshan section of the Yangtze River, said an official of the Ma'anshan branch of Changjiang Maritime Safety Administration.

The rescue team were also trying to salvage the sunken ferry. They retrieved a truck on Friday noon, the official said.

The accident occurred at about 1:40 a.m. Thursday when the ferry carrying 21 people sank in the Yangtze. The boat, which was not overloaded, was travelling from Ma'anshan City to Hexian County.

Investigation into the cause of the accident is underway.