Two Vietnamese fishermen died and 13 others were missing after two boats sank in rough waters off the Truong Sa (Spratly) Islands in the East Sea.

The two boats carrying a total of 93 fishermen were catching squid off the archipelago’s Song Tu Tay Island when strong winds and high waves sunk both vessels.

One of the boats sank with 54 fishermen aboard at 7:30 p.m. Monday and a nearby fishing boat was able to rescue 40 of them. Rescuers found two men on Tuesday morning, but they died soon after being pulled out of the water. 12 crew members from the boat remain missing.

The second boat sank in the same area with 39 fishermen aboard at 1 a.m. on Tuesday. Thirty-eight of them were rescued by a nearby fishing boat, leaving a 63-year-old man missing.

Quang Nam Province Border Guard Command said 20 fishing boats and three Navy ships are currently looking for the missing.

Heavy rain storms have been ravaging parts of central Vietnam for more than a week, causing severe flooding in Da Nang and nearby provinces. Two people were killed and more than 7,000 others have had to be evacuated so far.

An approaching tropical depression is forecast to worsen the situation, bringing strong winds and thunderstorms.