FILE - Fighters of Russian Volunteer Corps stand atop on an APC during press conference not far from the Ukraine's border with Russia in Sumy region, Ukraine, on May 24, 2023. Fighters from Ukraine made an attempt to cross into the town of Tetkino, which lies right on the border, the governor of Russia’s Kursk region, Roman Starovoit, said Tuesday. (AP Photo/Evgeniy Maloletka, File)

Ukraine launched a wave of long-range drones against targets deep inside Russia today, Russian officials said, hitting at least two oil facilities in the attack on eight regions of Russia in the latest display of Kyiv’s expanding drone capacity.

Also today, soldiers who Kyiv officials say are Russian volunteers fighting for Ukraine reported to have crossed the border into Russia, as they have several times during the war. Russia said it had beaten back attempted incursions, but it wasn’t possible to verify either side’s claims and the reports of border fighting were murky.

Alleged incursions reported occasionally during the war are the subject of claims and counterclaims, as well as disinformation and propaganda.

One Ukrainian drone struck and set ablaze an oil refinery in the Nizhny Novgorod region, according to regional governor Gleb Nikitin. That region is about 480 miles from the Ukraine border.

In another deep strike, a drone was shot down in the Moscow region, Moscow mayor Sergei Sobyanin said. Though it was brought down well south of the city center, the drone was close to Zhukovsky Airport, one of Mocow’s four international airports.

Another drone hit an oil depot in Oryol, 95 miles from Ukraine.

The strikes appeared to be evidence of Ukraine’s growing sophistication in domestic drone technology and its brashness in taking the war to Russia, after the Kremlin’s forces launched a full-scale invasion of Ukraine on Feb. 24, 2022.

Ukrainian President Volodymyr Zelenskyy said last year that his country had developed a weapon that hit a target 400 miles away, in an apparent reference to drones.

Ukraine has also increasingly deployed sea drones in the Black Sea, where it claims to have sunk Russian warships.

Kyiv’s forces are hoping for more military supplies from Ukraine’s Western partners, but in the meantime are struggling against a bigger and better-provisioned Russian army that is pressing hard at certain front-line points inside Ukraine.

Zelenskyy said that recent Russian advances have been halted and that the battlefield situation is now significantly better than in the previous three months.

“We had some difficulties due to the lack of artillery shells, long-range weapons, sky blocking and the high density of Russian drones,” Zelenskyy said in an interview with France’s BFM TV and Le Monde published late Monday on the Ukrainian presidential website.

Kyiv’s increasingly bold attacks behind the 1,500-kilometer (930-mile) front line running through eastern and southern Ukraine are coinciding with Russia’s presidential election. President Vladimir Putin is all but certain to win another six-year term by a landslide, but Ukraine’s attacks deep inside Russia undermine his attempts to show that life in Russia has been unaffected by the war.

The Russian Defense Ministry also said today that drones were intercepted over the Belgorod, Bryansk, Kursk, Leningrad and Tula regions of Russia.

Separately, the ministry said that one Tochka-U ballistic missile, with a range of about 40 miles, and eight Vampire missiles, which are fired from trucks and have a range of about 20 kilometers 12 miles, were shot down over Belgorod.

Russian border defenses are also reportedly being tested, though it was impossible to independently verify any side’s battlefield reports.

Fighters from Ukraine made an attempt to cross into the town of Tetkino, which lies right on the border, the governor of Russia’s Kursk region, Roman Starovoit, said today.

“There was an attempt by a sabotage and reconnaissance group to break through. There was a shooting battle, but there was no breakthrough,” he said in a video message on Telegram.

The Russian Defense Ministry also said four attacks by what it called Ukrainian sabotage and reconnaissance groups was driven back in Tetkino.

Meanwhile, soldiers who Kyiv officials are Russian volunteers fighting for Ukraine also claimed to have crossed the border into Russia.

Soldiers from the Freedom of Russia Legion, the Russian Volunteer Corps and the Siberian Battalion released statements and videos on social media claiming to show them on Russian territory. They said they wanted “a Russia liberated from Putin’s dictatorship.”

The authenticity of the video couldn’t be independently verified.

Russia’s Defense Ministry gave its own version of events, saying Ukrainian fighters made at least four attempts today to cross into Russia’s Belgorod region, but that all attacks were repelled by warplanes, artillery and missiles.

The representative of Ukraine’s intelligence agency, Andrii Yusov, told Ukrainska Pravda that the military groups are made up of Russian citizens.

“On the territory of the Russian Federation, they operate completely autonomously and independently,” he said.

In May, Russia alleged that dozens of Ukrainian militants crossed into one of its border towns in its Belgorod region, striking targets and forcing an evacuation, before more than 70 of the attackers were killed or pushed back by what the authorities termed a counterterrorism operation. Ukrainian officials have denied any link with the group.

Also today, an Il-76 heavy-lift transport plane of the Russian air force with 15 people on board crashed while taking off from an air base in the Ivanovo region in western Russia, the Defense Ministry said. Its statement didn’t specify whether there were any survivors. The ministry said that an engine fire during takeoff was the likely cause of the crash.