Several hundred mines have drifted into the Black Sea after breaking off from cables near Ukrainian ports, Russia's main intelligence agency and shipping market participants said.
The Black Sea is a major shipping artery for grain, oil and oil products.
"Due to storm weather, the cables connecting the mines to anchors were broken," Russia's Federal Security Service (FSB), the main successor to the Soviet-era KGB, said in a press release dated March 19, reports Reuters.
"Due to wind and water currents, the mines are drifting freely in the western part of the Black Sea," the FSB said.
The FSB said about 420 mines had broken loose.
Novorossiisk Port Authority, in a note seen by Reuters, said that shipping was at risk in the western Black Sea. Shipping sources said Turkish authorities had cautioned about the risk for those using the Dardanelles and Bosphorus straits.
