Tartous has become the primary base for maintaining and replenishing Russian submarines in the Mediterranean. Syria's two submarines and two frigates are based here, as are the country's amphibious and mine warfare forces. Also based at Tartous are more than a dozen fast attack craft (missile) and coastal patrol craft. Coastal defence missile and gun batteries protect the base. Russia is proposing to expand its presence at the base and also install S-300 (SA-10) strategic surface-to-air missiles to protect its naval forces in Syria.