Russia stops three Ukrainian Navy vessels from passing under the Kerch Strait Bridge by blocking it with a cargo ship. Russia claims they violated her territorial waters and ignored warnings. The navy vessels and their crews are seized after shots were fired. Russia says three Ukrainians were wounded. According to Ukraine, six of their sailors are wounded. Ukraine denies their ships did anything wrong.
Ukraine's Joint Forces Operation says Russian-led militants have mounted 43 attacks on Ukrainian troops in Donbas in the past 24 hours, using artillery systems and 120mm and 82mm mortars 10 times, with no casualties among the Ukrainian servicemen. According to intelligence data, two militants are killed and three others wounded.
Ukraine's domestic intelligence service, the SBU, reports that the March 2017 explosions at Balakliia military base in Eastern Ukraine were caused by a drone carrying a ZMG-1 thermite grenade. The explosions resulted in 1 death and 5 injuries.
Russia's Federal Security Service (FSB) says it has thwarted two armed Ukrainian incursions into Crimea with at least two killed, including one FSB officer, following a "massive fire fight" with "sabotage-terrorist" groups. Ukraine denies the Russian claims.
The Ukrainian government says it's regained control of the city hall in the eastern port of Mariupol from pro-Russian separatists. Administrative buildings have been taken over in at least a dozen towns in Eastern Ukraine.