The U.S. State Department on Thursday called on Russia to cease what it called "harassment of international shipping" in the Sea of Azov and Kerch Strait, accusing Moscow of trying to destabilize Ukraine.
"Russia's actions to impede maritime transit are further examples of its ongoing campaign to undermine and destabilize Ukraine, as well as its disregard for international norms," he department's spokeswoman Heather Nauert said in a statement.
Russia had prevented at least 16 commercial ships from reaching Ukrainian ports in recent weeks, she said.
(Reporting by Lesley Wroughton, editing by G Crosse)