The Ukrainian military said on Wednesday it carried out successful strikes against Russian air-defence systems in occupied Crimea.
Surface-to-air missile systems were damaged in airstrikes not far from the port city of Sevastopol, the Ukrainian General Staff said in a Facebook post.
Ammunition supplies were also destroyed in the overnight strikes, it said.
The Moscow-appointed governor of Sevastopol, Mikhail Razvozhayev, said earlier via the Telegram messaging service that a Ukrainian missile attack had been repulsed.
The claims made by both sides could not immediately be verified.
For several weeks, the Ukrainian army has been systematically trying to weaken Russian air defences in Crimea with drones, short-range missiles and cruise missiles. Satellite images and photos of destruction on the ground have provided evidence of successful attacks in isolated cases.
Ukraine has been fending off a Russian invasion for over two years. Including the Crimean peninsula, which was annexed in 2014, Russia controls a fifth of Ukraine's territory.