Photo from UNIAN Military expert, Colonel (Rtd) Oleh Zhdanov says Ukraine today has leverage to address Russia&#39;s threats to block entry into the Sea of Azov by starting a complete economic blockade of Crimea. Read alsoUkraine&#39;s defense minister responds to Russian threats to "shut down" Sea of Azov "We have leverage and we can start a comprehensive economic blockade of Crimea," the Ukrainian online news outlet Obozrevatel quoted Zhdanov as saying on November 20. "Why do our political leaders not denounce an agreement on the internal sea with the Russian Federation and not appeal to international institutions to bring international maritime law regarding the waters of the Sea of Azov in line with the concept of neutral waters and the notion of the state border to force Russia into following these rules?" he wondered. At the same time, the expert acknowledged that today Russia is able to close the Kerch Strait since it almost completely controls both the Sea of Azov and entry into it. Responding to a question whether international reaction is possible if vessels of third countries are affected by the blockade of the Sea of Azov, the expert said: "The question is how Russia will explain this blockage. If they do this based on the agreement on the joint use of the Sea of Azov as an internal sea, then no claims can be made against them today. If this looks like Russia&#39;s arbitrary behavior, then ship owners have the right to sue for losses and violations of international shipping rules." The Sea of Azov, a strategic arm of the Black Sea where Russia and Ukraine share the coastline, has become a flashpoint this year. Ukraine says Russia is preventing scores of vessels from reaching Ukrainian ports, namely Berdyansk and Mariupol, through spurious inspections and detentions.