Authorities from Russia and Ukraine have launched a rescue and cleanup operation in the Black Sea after heavy storms sank five ships, including an oil tanker. At least three sailors have died, and 20 remain missing. The oil tanker spilled more than a thousand tons of fuel oil after it split in half. Three cargo ships, each carrying more than 2,000 tons of sulfur, also sank. Officials said it could be the worst environmental disaster in the region in years and could take years to clean up.