Bulgarian navy vessels and helicopters were searching for the missing sailors off Bulgaria on Tuesday.
The Bulgarian Transport Ministry said the cargo ship Karam 1 sank late Monday after colliding with the Dutch tanker Alessandro DP, 10 miles off Cape Emine on Bulgaria’s coast.
The cargo ship sank an estimated half-an-hour after the collision, which did little damage to the tanker. The ministry ruled out any risk of pollution.
Five sailors of the cargo ship's crew of nine Syrians and an Egyptian were rescued and five were still missing.
The cargo ship was loaded with 2,600 tons of scrap metal en route to Istanbul, while the tanker was empty and heading to the nearby Bulgarian port of Varna.