The drone attack on an airbase in the Russian city of Pskov on Tuesday was launched from inside Russia, Ukraine’s military intelligence chief has said.
Kyrylo Budanov said two Ilyushin cargo planes were destroyed and two damaged. Russia says four were damaged.
Mr Budanov did not say whether the attack was carried out by Ukrainian or Russian operatives.
Ukraine’s drone attacks on Russia occur almost daily. It had already admitted the Pskov attack.
But Mr Budanov’s comments appear to end speculation that it was caused by a long-range weapon.
On Thursday President Volodymyr Zelensky said that a Ukrainian-made weapon had hit a target at a distance of 700km. Pskov is nearly 700km (434 miles) from the Ukrainian border.
“We are working from the territory of Russia,” Mr Budanov told the War Zone website on Thursday, without saying what type or quantity of drones were used.
He said the drones targeted the tops of the aircraft – the location of the fuel tanks and a critical section of the wing spar.
The damaged aircraft are long-range cargo planes, ideal for transporting troops and equipment over long distances and therefore valuable war assets for Russia.
Ukrainian officials are generally tight-lipped about attacks inside Russia, says BBC World Affairs correspondent Paul Adams. But it seems that as the campaign gathers pace, officials in Kyiv are more willing to claim them as part of the country’s war effort.
Meanwhile drone attacks on several locations in Russia continued overnight Thursday to Friday.
Unconfirmed reports say a factory making electronic parts for rockets in the town of Lyubertsy outside Moscow was hit.
However, Moscow Mayor Sergei Sobyanin said in his Telegram channel that the drones over Lyubertsy were shot down without causing any damage or casualties.
As with previous attacks in the Moscow area, a number of flights from Moscow airports were delayed or cancelled on Friday morning.
Kursk Region Governor Roman Starovoyt said one residential and one administrative building had been hit in the town of Kurchatov, close to the Kursk nuclear plant.
Ukraine is continuing its counter-offensive into Russian-occupied territory.
The Institute for the Study of War said on Thursday that advances were made near Bakhmut in the east, and in the west of Zaporizhzhia region.
