GUANGZHOU -- Seven crew members have been rescued from a cargo ship that sank off the coast of south China's Guangdong province Monday, local authorities said Tuesday.

Rescuers are trying to reach another five.

Twelve crew members went missing after a bulk ship carrying 5,000 tons of sand sank in the sea near the Pearl River estuary following a collision with another ship early Monday.

Huang Mutan, deputy head of Guangzhou maritime safety administration, said the seven were taken to hospital. One person is in the ICU and the other six are stable.

Those rescued said the other five are still trapped in the cabin, but rescuers have not yet located them.

The rescue work is ongoing, but it has been hampered by the rising tide since 5 pm.

About 300 people, including more than 20 divers, are involved in the rescue operation.

The two ships were registered in the eastern provinces of Jiangsu and Fujian.