Three fishermen went missing after their boat collided with a freighter Sunday at the sea off south China's island province of Hainan, according to local maritime authorities.

The Hainan Maritime Safety Administration received a report at noon, saying that a cargo ship, coded "Chenglu28", crashed into a small fishing boat in Qiongzhou Strait, and the latter sank immediately.

Five fishermen aboard the boat fell into the water and two of them were rescued by the freighter. The maritime authorities have dispatched two rescue vessels to search for the three missing fishermen.

When the accident occurred, the freighter, registered in Zhoushan in eastern Zhejiang Province, was en route to the Republic of Korea from Vietnam, said the authorities.