Chinese authorities searched Monday for 12 crew members who disappeared after two cargo ships collided before dawn off the coast of southern Guangdong province, according to state media.

A ship carrying 5,000 tons of sand sank after the collision, the Guangzhou maritime search and rescue centre said. But the second ship carrying over 5,000 tons of steel managed to make it to shore, the state-run China National Radio reported.

Two crew members from the sunken ship and eleven sailors from the steel ship have been rescued, the Guangzhou center said. The collision occurred at about 3:00 am on Monday near the Pearl River estuary.

Some 30 rescue ships, one helicopter and other ships that happened to be nearby were participating in search efforts. Authorities have launched an investigation into the cause of the accident, according to the official Xinhua news agency.