Ukraine said Friday it had destroyed at least six Russian military planes at an airbase in the southern Rostov region in a barrage of overnight drone attacks.
Kyiv launched once of its largest overnight attacks in weeks, firing more than 50 drones at Russian territory, according to Russia's defense ministry.
A security source in Kyiv told AFP that an attack on the Morozovsk air base in Russia's southern Rostov region had destroyed at least six Russian planes and "another eight were heavily damaged".
"This is an important special operation that will significantly reduce the combat potential of the Russians," the source said, adding that the attack was carried out by the SBU security service and the military.
There was no immediate response from Russia and AFP was unable to verify the claims.
Russia said 44 of the 53 drones Kyiv fired overnight targeted the southern Rostov region, which sits just across the border from Ukraine and is home to a number of major military sites, including its command headquarters for the offensive.
"During the night and on the morning of April 5, the Kyiv regime tried to commit several terrorist attacks with aerial drones which were foiled," the defense ministry said.
Rostov governor Vasily Golubev said a drone attack on the Morozovsk district, where the airbase is located, had caused "insignificant damage" to a power station that had cut electricity supplies to around 600 residents.
He also reported windows were blown out in an apartment building but made no mention of the air base.
Russia rarely comments on Ukrainian claims of successful strikes.
Kyiv has stepped up its aerial attacks on Russian territory in recent months, targeting both military sites and energy facilities in a bid to disrupt Russia's supply of fuel and equipment for its invasion.
On Tuesday, Ukrainian drones hit the central Tatarstan region -- around 1,100 kilometers (680 miles) from the countries' shared border -- in one of the deepest Ukrainian attacks of the two-year war.
Kyiv said the strike hit a major oil refinery and a factory assembling explosive drones.
Other Ukrainian drone attacks in the early hours of Friday targeted the Belgorod and Kursk border regions, as well as Saratov and Krasnodar.
In Saratov, the governor said a drone had targeted Engels, a city around 500 kilometers (300 miles) from the border that is home to a major Russian air base that has previously been hit.
Ukraine's air force meanwhile said Russia launched five missiles and 13 drones at its territory overnight.
Kyiv said it downed the 13 drones, but did not say anything about the missiles, which targeted the northeastern Kharkiv region.
Russian-installed authorities in areas of Ukraine occupied by Moscow's forces also reported Ukrainian strikes on Friday.
Five people were injured, two seriously, in a drone attack on the Russian-controlled part of the southern Kherson region, while seven were injured in a strike on Gorlivka in the eastern Donetsk region, Moscow-appointed officials said.
On the battlefield, Russian forces are seeking to press their advantage with Ukraine facing shortages of both manpower and ammunition amid delays to the delivery of Western aid.
Russian-installed officials have claimed Moscow's forces are advancing on Chasiv Yar, a town in Ukraine's eastern Donetsk region.
Both Ukrainian and Russian military bloggers with links to the armed forces said Friday that Russian troops had reached the outskirts of the town.
