AFP via Getty ImagesFierce fighting in Russia’s Kursk region has entered its third day, with “ongoing” efforts to expel Ukrainian forces from the country, Moscow’s defence ministry said.
Russia said at least 1,000 Ukrainian troops, backed by tanks and armored vehicles, crossed the border on Tuesday.
Kursk Deputy Governor Andrei Belostotsky said on Thursday that about 3,000 people had been evacuated from the region because of ongoing military clashes that have left at least four people dead.
The Ukrainian military has remained steadfastly silent on the allegations, but a senior adviser to President Volodymyr Zelensky has blamed “clear Russian aggression” for any “military action”.
“War is war, it has its own rules, where the aggressor will certainly reap the corresponding results,” added Mykhailo Podolyak, a longtime aide to President Zelensky.
The Russian Defense Ministry said advances and “attempted breakthroughs” by Ukrainian military units in the Sudzhansky and Korenevsky districts of Kursk were prevented by joint efforts of the Federal Security Service (FSB) and the military.
The Kremlin said Ukraine had lost 660 servicemen since the start of fighting in Kursk. Mr Belostotsky said Kyiv forces were starting to withdraw from the area.
The BBC cannot verify death tolls in ongoing conflicts, and death tolls reported by opposing sides often do not reflect the true situation.
In an update on Thursday, Moscow said Kyiv had lost 82 armored vehicles, a figure much higher than initial reports that 11 tanks and more than 20 armored vehicles had crossed into Russia near the town of Sudzha on Tuesday morning.
Also on Thursday, Russia offered, for the third day in a row, to prevent Ukrainian troops from entering Kursk.
But on Wednesday, Russian military chief Valery Gerasimov said the “advancement” in the Kursk region had been halted, as Russian forces “continue to destroy the enemy in areas directly adjacent to the Russian-Ukrainian border”.
Meanwhile the FSB made a similar statement on Tuesday, when initial reports of possible Ukrainian infiltration emerged.
In its latest report, the Institute for the Study of War, a respected think tank, said geo-located footage from the past two days showed Ukrainian armored vehicles advancing to a position 10km (6.2 miles) from the Kursk area.
Meanwhile, footage verified by the BBC shows fighter jets flying low overhead in the area in recent days.
Russia’s military leadership is under intense scrutiny at home, as several popular and well-informed pro-war Telegram channels suggest the situation on the ground is not as stable as the Kremlin has suggested.
The influential pro-war Rybar Telegram channel strongly criticized the highest ranks of the Russian military on Wednesday, saying that “in two months, all the information that has been sent to headquarters is useless”, adding that there was still enough time “to make appropriate decisions”.
Rybar’s concerns are shared by many other pro-war bloggers.
Local leaders in the Kursk region, both in Russia and Ukraine, have ordered residents to evacuate the area since news of the incursion.
On Wednesday, the head of Ukraine’s Sumy region, Volodymyr Artyukh, ordered the evacuation of areas bordering Kursk.
Meanwhile, in Russia’s Belgorod region, governor Vyacheslav Gladkov said on Thursday that settlements across his province had come under attack by Ukrainian forces in the past 24 hours.
This is not the first time that Ukraine-based militants have infiltrated Russia. Several anti-Kremlin Russian groups carried out raids last year, but were repelled.
In March, the forces again entered the Belgorod and Kursk regions, where they clashed with Russian security forces.
On Wednesday evening, Ukrainian parliament member Oleksiy Honcharenko said the Ukrainian military had established control over the Sudzha gas hub, a major gas facility involved in the transportation of natural gas from Russia to the EU via Ukraine, and that the operation was continuing despite the war.
This is the only point for Russian gas to enter the EU.
But on Thursday, gas was still said to be flowing from Sudzha.
Russia’s National Guard said it had increased security around the Kursk nuclear power plant, located about 70km northeast of Sudzha.
Over the past few months, Russia has made some gains in eastern Ukraine as many of Kyiv’s ground forces have faced sustained attacks in the eastern Donbas region.
In a recent interview, the head of Ukraine’s defense intelligence agency, Kyrylo Budanov, said the main offensive by Russian forces “is expected to end within one and a half to two months.”
