HANGZHOU -- Emergency crew have found eight bodies of the 29 sailors of a ship that sank off east China after its collision with another ship late Saturday night.

Twelve sailors have been rescued and the other nine are still missing, sources with the maritime safety administration of Zhejiang Province revealed on Sunday.

The collision occurred around 11 p.m. Saturday on the sea near the Langgang islands, northeast of Zhoushan Island, Zhejiang Province, when a cargo ship belonging to a transport company in Shenzhen crashed with another one registered in Hong Kong.

The Hong Kong ship, "Huirong", sank immediately and all its 29 sailors on board were marooned on the sea. The other ship," Pengyan", was from Shenzhen Ocean Shipping Co., Ltd.

The Zhejiang maritime safety administration immediately activated an emergency plan to rescue the sailors after it received a report about the accident, said an official with the administration.

More than 40 vessels and three helicopters from the East China Sea Fleet, East China Sea Rescue Bureau, and local maritime safety authorities in Zhejiang have joined the rescue efforts.

Minister of Communications Li Shenglin and Vice Minister Weng Mengyong arrived at the China Maritime Search and Rescue Center to direct the rescue operation.

The cause of the collision is being investigated. Rescuers are still searching for the missing.

Meanwhile, workers have begun to clear oil leaking into the sea and set location marks for the Hong Kong ship.