Reports from Russia say there has been a drone attack on the airport of the north-western city of Pskov.
The local governor said the military was repelling an attack. He uploaded video showing a large fire while an explosion could also be heard.
An unconfirmed Russian media report says four Ilyushin 76 transport planes were damaged at the airport.
Pskov is more than 600km (372 miles) away from Ukraine, close to the border with Estonia.
Ukraine has not said it was involved in the incident but it rarely comments on attacks inside Russia.
In recent weeks the country is believed to have increased its use of explosive drones to attack targets inside Russia.
In other developments:
- Russia's military said its forces had destroyed four rapid Ukrainian boats carrying a total of about 50 soldiers in an operation on the Black Sea around midnight Moscow time (21:00 GMT). Ukraine did not comment immediately
- The Russian military said it had downed three Ukrainian drones over the southern region of Bryansk and one over the central region of Oryol
- Russia's Tass news agency reported that airspace above Moscow's Vnukovo airport had been closed.
"The defence ministry is repelling a drone attack on Pskov's airport," Pskov regional governor Mikhail Vedernikov said on Telegram.
Mr Vedernikov, who said he was at the scene of the attack, added: "According to preliminary information, there are no victims."
Tass, quoting emergency services, reported the damage to the aircraft.
"As a result of the drone attack, four Il-76 aircraft were damaged," it said. "A fire broke out and two planes burst into flames."
There were no immediate reports on other Russian state news agencies of planes being damaged.
A drone attack on Russia's Belgorod region killed three people last week, hours after another drone hit central Moscow, Russian officials said.
It came just days after a flagship Russian long-range bomber was destroyed in a Ukrainian drone strike near the city of St Petersburg.
Pskov region was previously targeted by drones in late May.
Although Ukraine has not said it carried out specific drone strikes, President Volodymyr Zelensky has previously said that attacks on Russian territory are an "inevitable, natural and absolutely fair process" as the war with Russia continues.
