Authorities confirmed 21 people dead in the capsizing of a tugboat with an international team on a test voyage in eastern China, after rescuers dragged the overturned vessel to shallow waters and scoured it Saturday.

One person remained missing, and rescuers continued to search the cockpit of the vessel as well as nearby sections of the Yangtze River in the province of Jiangsu, the state-run Xinhua News Agency said.

The newly built, 30-meter (98-foot) long Wanshenzhou 67 was on a test voyage Thursday in the river's Fubei Channel when it suddenly turned over.

The ship's owner, parts suppliers and engineers were among the 25 people aboard for the test, including eight foreigners: Four Singaporeans, an Indian, an Indonesian, a Japanese and a Malaysian.

Three people were rescued, all Chinese, including one man identified as an interpreter who was freed when rescuers cut through the bottom of the boat's hull early Friday — a full 14 hours after it went down.

Officials did not immediately give the missing person's nationality.

An official form the Jiangsu maritime search and rescue center, who declined to give his name, confirmed that 21 people were dead.

Swift currents had hampered the operation, and it was not until Saturday morning when rescue teams were able to pull the vessel to the surface and to shallow waters for a thorough search inside.

The 368-ton ship was built by Anhui Bengbu Shenzhou Machinery Co. Ltd.