The four had been on board a fishing vessel, together with11 others, when it sank near Phu Quy island on July 10.
The rescued men said their boat sank in strong seas, and the15 workers on board escaped in two basket boats, one carrying seven people andanother with eight. The boat with seven people drifted towards the Truong Sa(Spratly) archipelago.
The Office of the National Committee for Disaster Responseand Search and Rescue said that after receiving a report of the incident, itdispatched an airplane, while the Ministry of National Defence sent a ship tothe scene.
At 9.30am on July 20, the rescue ship located a life vesselcarrying seven crewmembers, but three had already succumbed to exhaustion.
The search for eight other crewmembers boarding theremaining basket boat is ongoing./.