President Volodymyr Zelensky said on Friday that Ukrainian troops had successfully struck targets in Russia overnight, using Ukrainian long-range "Long Neptune" missiles.
He added that these attacks are becoming increasingly successful over time.
"Last night, our fighters successfully used 'Long Neptune' against certain objects on Russian territory, and this is our appropriate response to Russia's continued terror," Zelensky wrote on X.
"Ukrainian missiles are delivering increasingly better and more accurate results almost every month," Zelensky added.
These missiles, which were successfully tested in combat in March, have a range of 1.000 km, Zelensky said at the time, without mentioning the location where the tests took place.
Last week, the Ukrainian General Staff announced that the effective use of domestic long-range weapons, including Neptune-type missiles, is increasing.
"This is causing the enemy a lot of concern," the General Staff statement said on Tuesday.
Zelensky did not name any specific target. Two sources told Reuters that Russia's Black Sea oil port of Novorossiysk had suspended oil exports after a drone attack from Ukraine, but Ukraine has not claimed responsibility for the attack.