MOSCOW, May 25. /TASS/. Magnetic mines were planted on a vessel that arrived at the port of Ust-Luga in northwestern Russia from Belgium, with explosives in each of them weighing about 7 kg, the press office of Russia’s Federal Security Service (FSB) reported.

"During the inspection of the underwater part of the vessel’s hull, divers discovered external magnetic objects attached in the area of the engine room and showing the signs of explosive devices. After conducting a survey with the use of an underwater drone, specialists of the inter-agency group of bomb technicians made a clear-cut conclusion that the objects were explosive devices produced as magnetic sea mines presumably in one of NATO countries, using industrial production tools," the press office said in a statement.

The plastic explosive in each mine weighed about 7 kg, it specified.