Officials in Ukraine said Thursday they have seized a Russian tanker moored in the Black Sea in a move that could undermine a much-anticipated prisoner swap between the two countries. The Ukrainian Security Service (SBU) said in a statement that it seized the Russian tanker moored in a Ukrainian Black Sea port on Wednesday. Authorities said that the tanker was used in a Russian operation to block Ukrainian vessels from sailing through the Kerch Strait between the Black Sea and the Sea of Azov in November last year.
