A U.S. Marine assigned to U.S. Marine Corps Forces Europe and Africa takes the beach after an amphibious landing in Nikolaev, Ukraine, during exercise Sea Breeze 2017, July 19. Sea Breeze is a U.S. and Ukraine co-hosted multinational maritime exercise held in the Black Sea and is designed to enhance interoperability of participating nations and strengthen maritime security within the region. (U.S. Marine Corps photo by Cpl. Sean J. Berry/Released)

U.S. Marines assigned to U.S. Marine Corps Forces Europe and Africa and Ukrainian marines secure the beach after an amphibious landing in Nikolaev, Ukraine, during exercise Sea Breeze 2017, July 19. Sea Breeze is a U.S. and Ukraine co-hosted multinational maritime exercise held in the Black Sea and is designed to enhance interoperability of participating nations and strengthen maritime security within the region. (U.S. Marine Corps photo by Cpl. Sean J. Berry/Released)

A U.S. Marine assigned to U.S. Marine Corps Forces Europe and Africa secures the beach after an amphibious landing in Nikolaev, Ukraine, during exercise Sea Breeze 2017, July 19. Sea Breeze is a U.S. and Ukraine co-hosted multinational maritime exercise held in the Black Sea and is designed to enhance interoperability of participating nations and strengthen maritime security within the region. (U.S. Marine Corps photo by Cpl. Sean J. Berry/Released)

A U.S. Marine with Black Sea Rotational Force 17.1 launches an unmanned aerial vehicle during exercise Sea Breeze 2017 in Nikolaev. Ukraine, July 19. Sea Breeze is a U.S. and Ukraine co-hosted multinational maritime exercise held in the Black Sea and is designed to enhance interoperability of participating nations and strengthen maritime security within the region. (U.S. Marine Corps photo by Cpl. Sean J. Berry/Released)

U.S. Marines with Black Sea Rotational Force 17.1 load up into a transport vehicle with Ukrainian marines in Nikolaev, Ukraine, during exercise Sea Breeze 2017, July 19. Sea Breeze is a U.S. and Ukraine co-hosted multinational maritime exercise held in the Black Sea and is designed to enhance interoperability of participating nations and strengthen maritime security within the region. (U.S. Marine Corps photo by Cpl. Sean J. Berry/Released)

U.S. Marines with Black Sea Rotational Force 17.1 and Ukrainian marines load up into a transport vehicle in advance of an amphibious landing in Nikolaev, Ukraine, during exercise Sea Breeze 2017, July 18. Sea Breeze is a U.S. and Ukraine co-hosted multinational maritime exercise held in the Black Sea and is designed to enhance interoperability of participating nations and strengthen maritime security within the region. (U.S. Marine Corps photo by Cpl. Sean J. Berry/Released)

A U.S. Marine with Black Sea Rotational Force 17.1 prepares for an amphibious landing in Nikolaev, Ukraine, during exercise Sea Breeze 2017, July 18. Sea Breeze is a U.S. and Ukraine co-hosted multinational maritime exercise held in the Black Sea and is designed to enhance interoperability of participating nations and strengthen maritime security within the region. (U.S. Marine Corps photo by Cpl. Sean J. Berry/Released)

U.S. Marines assigned to U.S. Marine Corps Forces Europe and Africa secure the beach after an amphibious landing in Nikolaev, Ukraine, during exercise Sea Breeze 2017, July 19. Sea Breeze is a U.S. and Ukraine co-hosted multinational maritime exercise held in the Black Sea and is designed to enhance interoperability of participating nations and strengthen maritime security within the region. (U.S. Marine Corps photo by Cpl. Sean J. Berry/Released)