TOPSHOT - A serviceman walks near a Ukrainian military helicopter flying during military drills near Urzuf village not far from the city of Mariupol, eastern Ukraine on November 29, 2018. - Ukraine's president imposed martial law in border regions on November 28, 2018 for 30 days in 10 regions bordering Russia, the Black Sea and the Azov Sea, after Russian forces seized three of Kiev's ships off the coast of Crimea on November 25, sparking the most dangerous crisis between the ex-Soviet neighbours in years. (Photo by Sega VOLSKII / AFP)