Two cargo ships collided off the coast of central Quang Nam Province early Wednesday, killing three and leaving two sailors missing.
According to eyewitnesses, the Phuc Hai 05 en route from Indonesia to Da Nang City crashed into the Binh Minh 28 en route from Thanh Hoa to An Giang Province.
Fifteen minutes after the collision, the Binh Minh cargo ship sank with 11 crew members on board.
Minh Hai 126, a ship not far from the accident site, rescued six sailors.
A rescue ship found two other sailors but they died on the way to hospital due to severe injuries. Later Wednesday, local fishing boats found another sailor's body, bringing the death toll to three.
Rescuers are still searching for two missing people.
The cause of the accident is not known, but bad weather and thick fog may be a contributing factor, Lao Dong (Labor) newspaper reported.
The Binh Minh 28, which has a capacity of 2,000 tons, was transporting 1,880 tons of clinker when it crashed into Phuc Hai 05.
The same day, a fishing boat sank off the coast of southern Ba Ria-Vung Tau Province due to rough seas. Only one of the seven crew members has been rescued so far; six others are still missing.
A rescue boat has been sent to search for the missing people.
A day earlier, on Tuesday, the Zone 2 Maritime Search and Rescue Coordination Center (Da Nang MRCC) received an SOS from a fishing boat which broke down while fishing off the waters of central Binh Dinh Province, Tuoi Tre newspaper reported.
The boat with 28 crew members was 200 nautical miles from the mainland when it sent the SOS. Da Nang MRCC said it had lost contact with the boat on Wednesday.