Russia said on Wednesday that it was fighting intense battles against Ukrainian forces which had penetrated the Kursk region near a major natural gas transmission hub in one of the largest incursions into Russia since the war began in February 2022.
Russia has advanced this year after the failure of Ukraine's 2023 counteroffensive to achieve any major gains, and has taken 162 sq miles of territory from Ukrainian forces since June 14, Russian officials said.
Ukraine struck back on Tuesday - and the battles continued through the night into Wednesday as Ukrainian forces pushed to the northwest of the border town of Sudzha, 330 miles southwest of Moscow, Russia's defense ministry said.
KYIV'S FORCES ARE UP AGAINST A CONCERTED RUSSIAN PUSH IN EASTERN UKRAINE, A MILITARY OFFICIAL SAYS
"The Kyiv regime has launched another major provocation," President Vladimir Putin told members of the Russian government about the Kursk attack.
Sudzha is the last operational trans-shipping point for Russian natural gas to Europe via Ukraine: the Urengoy–Pomary–Uzhhorod pipeline carried about 14.65 billion cubic meters of gas in 2023, or about half of Russia's natural gas exports to Europe.
Ukraine's gas transmission operator said Russian natural gas was transiting to European consumers normally. Just 60 km away to the northeast is Russia's Kursk nuclear power station.
The battles around Sudzha come at a crucial juncture in the conflict, the biggest land war in Europe since World War Two. Ukraine is losing territory and Kyiv is deeply concerned that U.S. support could drop off if Donald Trump wins the November election in the United States.
Trump has said he would end the war, so both Russia and Ukraine are keen to gain the strongest possible bargaining position on the battlefield while pinning down Russian forces and showing the West that it can still mount major battles.
Russian military bloggers reported intense battles, with some suggesting that Ukraine had opened a new front. Ukraine has not commented on the battles. Russia sent reserves to help shore up Russian defenses.
The chief of Russia's general staff, Valery Gerasimov, told Putin that Russian forces were battling Ukrainian forces near the border and that Russia would push them back to the border.
Russia's defense ministry said it had already destroyed 50 armored vehicles, including seven tanks, eight armored personnel carriers, three infantry fighting vehicles and 31 armored combat vehicles in the area.
Putin said Ukrainian forces were firing "indiscriminately" at a range of civilian targets in the region, and said that he would shortly have a meeting with top defense ministry and Federal Security Service officials.
Both Kyiv and Moscow say they do not target civilians in the war, triggered by Russia's full-scale invasion nearly two and a half years ago.
Russian Telegram channels carried unverified footage of shelled houses. Alexei Smirnov, the acting governor of the Kursk region, said there were casualties but gave no exact toll, and called on citizens to donate blood.
Forces describing themselves as voluntary paramilitaries fighting on Ukraine's side penetrated parts of Belgorod and Kursk regions this year, triggering a major push by Russian troops to carve out a buffer zone in Ukraine's northeast.