Ukraine's armed forces have conducted drills near the borders of Russian-annexed Crimea, the defense ministry said in a statement on Wednesday, amid growing tensions on the country's frontiers.
The drills simulated Ukrainian marines, tanks and aircraft repelling an enemy attack, the defense ministry said. It also released footage showing marines maneuvering with large-caliber machine guns, grenade launchers, tanks and helicopters.
Earlier this month Ukrainian border guards, police and the national guard also held drills on the border with Belarus aiming to protect the country from possible attempts by migrants to breach the frontier.
Ukrainian authorities have said Russia has left military units near the Ukrainian border after exercises, with the number of troops in the area now totaling at least 90,000 and the forces holding a series of large-scale drills.
US officials said they were worried about the build-up of Russian military power near Ukraine and the migrant stand-off between Belarus, a close ally of Russia, and the European Union.
But Russia has complained about what it has called a dangerous increase in military activity by the United States and its allies in the Black Sea region, with greater Western spy plane activity, more strategic bombers flights and the presence of two US warships.
Crimea, the Black Sea peninsula, was annexed by Russia from Ukraine in 2014.
This spring, Moscow alarmed Kyiv and Western capitals by building up more than 100,000 of troops along the border with Ukraine, though it later ordered them back to base.