Blood stains are seen on the crashed accident. [File photo]

A pilot believed to be responsible for a deadly yacht accident in east China's Jiangsu province has been confirmed to be driving under the influence of alcohol, local authorities said Sunday.

Blood test on the pilot, Feng Ke'er, showed that there were 54 milligrams of alcohol in per 100 milliliters of blood, 34 milligrams higher than the permitted level, sources with Suzhou municipal government said.

Four students from two Shanghai-based universities were killed and four others injured on Wednesday when their yacht, piloted by Feng, hit the cable of a cargo ship on the lake of Taihu in Suzhou, Jiangsu province.

Feng was believed to be operating the yacht between the cargo ship and a tug boat, and the yacht hit the drawing cable between them, according to the Suzhou's publicity authorities.

Feng and two pilots of the cargo ship and the tug boat have all been taken into police custody for investigation, and police drew blood sample from Feng shortly after the accident.

Feng was caught on video denying that there was anyone overboard while some surviving students ashore insisted that someone from the yacht was missing and asked him to go back and have a search and rescue.

The passengers were reportedly not wearing life vests in the yacht.

A further investigation into the accident is under way.