An explosion sank a sanctioned Russian cargo ship in the Mediterranean Sea on Monday night, Russian authorities said, leaving two crew members missing.

A Russian cargo ship called Ursa Major sank in the Mediterranean Sea overnight after an explosion ripped through its engine room and two of its crew are still missing, the Russian Foreign Ministry said on Tuesday.

A "terrorist act" sank the cargo ship that went down in international waters in the Mediterranean this week, the Russian state-owned company that owns the vessel said Wednesday. The ship sank in international waters off Spain in the early hours of Tuesday after having sent a distress call for help on Monday.