Russian troops are fighting Ukrainian forces in the Kursk region in the third day of one of the largest cross-border incursions of the war, the Russian Defense Ministry said Thursday.

A ministry statement said the Russian military and border guards have blocked Ukrainian forces from advancing deeper into Kursk region in southwest Russia and that the army is attacking Ukrainian combatants who are trying to advance on the area from Ukraine’s Sumy region.

“Attempts by individual units to break through deep into the territory in the Kursk direction are being suppressed,” the ministry said.

The Institute for the Study of War, a Washington-based think tank, said that as of Wednesday, Ukrainian troops had advanced as much as 10 kilometers (6 miles) into Russian territory, but that information wasn’t confirmed. Ukrainian officials haven’t commented on the scope of the operation around the town of Sudzha.

“The enemy has not advanced a single meter, on the contrary, it is retreating. The enemy’s equipment and combat forces are being actively destroyed. We hope that in the near future … the enemy will be stopped,” the Kursk region’s acting deputy governor Andrei Belostotsky said Thursday, according to state news agency RIA-Novosti.

Russian President Vladimir Putin on Wednesday described the incursion as a “large-scale provocation.”

Putin met with his top defense and security officials to discuss what he called the “indiscriminate shelling of civilian buildings, residential houses, ambulances with different types of weapons.” He instructed the Cabinet to coordinate assistance to the Kursk region. The fighting is about 500 kilometers (320 miles) from Moscow.

Army chief of staff Valery Gerasimov told Putin at the meeting via video link that about 100 Ukrainian soldiers had been killed in the battle and more than 200 others were wounded, Russian news agencies reported.

The Ukrainian shelling, meanwhile, killed at least two people — a paramedic and an ambulance driver — and wounded 24 others, Russian Foreign Ministry spokesperson Maria Zakharova said in a statement Wednesday.

It wasn’t possible to independently verify the Russian claims. Disinformation and propaganda have played a central role in the war, now in its third year. John Kirby, the White House’s national security spokesman, declined to comment on the operation and said the Biden administration has reached out to the Ukrainians to better understand what happened.

The cross-border foray would be among Ukraine’s largest since Russia launched its full-scale invasion on Feb. 24, 2022, and unprecedented for its deployment of Ukrainian military units.

Kyiv’s aim could be to draw Russian reserves to the area, potentially weakening Moscow’s offensive operations in several parts of Ukraine’s eastern Donetsk region, where Russian forces have increased attacks and are advancing gradually toward operationally significant gains.

But it could risk stretching outmanned Ukrainian troops further along the front line, which is more than 1,000 kilometers (620 miles) long.

Even if Russia were to commit reserves to stabilize the new front, given its vast manpower and the relatively small number of Ukrainian forces engaged in the operation, it would likely have little long-term impact.

However, the operation could boost Ukrainian morale at a time when Kyiv’s forces are facing relentless Russian attacks and are expected to face more in coming weeks.

Several Ukrainian brigades stationed along the border region said that they couldn’t comment. Ukraine’s Defense Ministry and General Staff said that they wouldn’t comment.

Russian forces have swiftly repelled previous cross-border incursions, but not before they caused damage and embarrassed authorities.

Responsibility for previous incursions into Russia’s Belgorod and Bryansk regions has been claimed by two murky groups: the Russian Volunteer Corps and the Freedom of Russia Legion, which are made up of Russian citizens and have fought alongside Ukrainian forces.

Some Russian war bloggers who have proved knowledgeable about the war said that Ukrainian soldiers were in Kursk.

Rybar, a Telegram channel run by Mikhail Zvinchuk, a retired Russian Defense Ministry press officer, said that Ukrainian troops had seized three settlements in the region and continued to fight their way deeper in. It also said that Ukrainian forces captured the Sudzha gas transit station, about 8 kilometers (5 miles) from the border. Russian officials haven’t confirmed the gains.

Another pro-Kremlin military blog, Two Majors, claimed that Ukrainian troops had advanced up to 15 kilometers (9 miles) into the region.

Neither claim could be independently verified.

The Kursk region’s border with Ukraine is 245 kilometers (150 miles) long, making it possible for saboteur groups to launch swift incursions and capture some ground before Russia deploys reinforcements.

(AP)