Russia is struggling with a worsening soldier shortage as it attempts to stave off massive incursions by Ukrainian forces, insiders have claimed.

In an indication of how seriously the Kremlin is taking the situation, Belarusian President Alexander Lukashenko has ordered the transfer of military equipment to the Russian Armed Forces in the Kursk region.

Russia said Tuesday that its forces checked an effort by Volodymyr Zelensky's troops to expand a stunning weeklong incursion as a Ukrainian Foreign Ministry spokesperson insisted Kyiv has no intention of occupying Russian territory.

Russian army units, including fresh reserves, aircraft, drone teams and artillery forces, stopped Ukrainian armoured mobile groups from moving deeper into Russia near the Kursk settlements of Obshchy Kolodez, Snagost, Kauchuk and Alexeyevsky, a Russian Defence Ministry statement said.

The growing shortage of personnel has prompted Russia to boost recruitment bonuses to avoid a repeat of the unpopular mobilisation of 2022.

Russia is understood to need 30,000 recruits a month to fill its ranks - but it appears to be struggling to keep pace.

One insider told Bloomberg: "The scale of Russian losses and inadequate replacement levels make it increasingly difficult to sustain the current strategy of slowly grinding out advances in Ukraine.

"There’s no longer any discussion about seizing Kyiv and other cities because Russia doesn’t have the manpower.”

Minsk-based news agency Belnovosti, citing unnamed sources in the country’s defence ministry, said the recent delivery of materiel was related to "an urgent request from the Russian side" due to losses and a lack of equipment in Kursk and elsewhere.

Ukrainian Foreign Ministry spokesperson Heorhii Tykhyi yesterday said the cross-border operation was aimed at protecting Ukrainian land from long-range strikes launched from Kursk.

He added: “Ukraine is not interested in taking the territory of the Kursk region, but we want to protect the lives of our people.”

Russia had launched more than 2,000 strikes from the Kursk region in recent months using anti-aircraft missiles, artillery, mortars, drones, 255 glide bombs and more than 100 missiles, Mr Tykhyi argued.

He continued: "The purpose of this operation is to preserve the lives of our children, to protect the territory of Ukraine from Russian strikes."

The commander of the Ukrainian military, Oleksandr Syrskyi, said in a video posted Tuesday to President Volodymyr Zelenskyy’s Telegram channel that Ukraine now controls 74 settlements in the Kursk region.

Ukrainian troops have continued to advance, gaining control of more than 15 square miles of territory in the past 24 hours, Mr Syrskyi explained.

Mr Syrskyi said: “Fights are ongoing along the entire front line. The situation, despite the high intensity of combat, is under control."

Ukraine’s Western partners have said the country has the right to defend itself, including by attacking across the border. Polish Prime Minister Donald Tusk said yesterday that he backed the Ukrainian operation, though he said Kyiv officials did not consult him about it beforehand.

Russian military actions in Ukraine bear "the hallmarks of genocide, inhumane crimes, and Ukraine has every right to wage war in such a way as to paralyse Russia in its aggressive intentions as effectively as possible,” Mr Tusk added.

Kremlin forces intensified their attacks in eastern Ukraine. Ukraine’s General Staff said yesterday that over the previous 24 hours, Russian troops launched 52 assaults in the area of Pokrovsk, a town in Ukraine’s Donetsk region that is close to the front line. That's roughly double the number of daily attacks there a week ago.

Ukraine's shorthanded army has struggled to hold back the bigger, better-equipped Russian forces in Donetsk.

The Ukrainian military claims that its charge onto Russian soil which began August 6 has already encompassed about 386 square miles of Russian territory. The goals of the swift advance into the Kursk region have been a closely guarded military secret.

Analysts say a catalyst may also have been Ukraine’s desire to ease pressure on its front line by attempting to draw the Kremlin’s forces into defending Kursk and other border areas. If so, the increased pressure around Pokrovsk suggests Moscow did not take the bait.

Ukraine’s ambitious operation - the largest attack on Russia since World War II - has rattled the Kremlin. It compelled Russian President Vladimir Putin to convene a meeting Monday with his top defence officials.

Ukraine seems to have assembled thousands of troops - some Western analysts estimate up to 12,000 - on the border in recent weeks without Russia noticing or acting.

About 121,000 people have been evacuated from Kursk or have fled the areas affected by fighting on their own, Russian officials say. The Institute for the Study of War, a Washington-based think tank, said it has seen geolocated footage indicating that Ukrainian forces advanced as much as 15 miles from the border.

The Russian Defence Ministry appeared to support that claim, saying it had also blocked an attack by the units of Ukraine's 82nd Air Assault Brigade toward Maryinka, which is about that distance from Ukraine.

Russian state television showed residents from evacuated areas lining up in buildings and on the street to receive food and water. Volunteers were pictured distributing bags of aid, while officials from the country’s Ministry of Emergency Situations helped people, including children and older people, off buses.

Speaking to Russian television, one man said: “There is no light, no connection, no water. There is nothing. It’s as if everyone has flown to another planet, and you are left alone. And the birds stopped singing.

"Helicopters and planes fly over the yard and shells were flying. What could we do? We left everything behind.”

A motive behind Ukraine’s bold dive into Russia was to stir up unrest, admitted Putin, while stressing such efforts would fail.

The successful border breach also was surprising because Ukraine has been short of people at the front as it waits for new brigades to complete training.

Dara Massicot, an analyst at the Carnegie Endowment, said the Ukrainian breakthrough was a smart move because it exploited gaps between various Russian commands in Kursk: border guards, Ministry of Defense forces and Chechen units that have been fighting on Russia's side in the war.

Russian command and control is fractured in Kursk, Massicot said on X on Monday.

The Ukrainian Army's General Staff announced Tuesday that it was establishing a 12-mile restricted-access zone along the Russian-Ukrainian border in the northeastern Sumy region, which borders Kursk.

The measures were introduced because of the increasing intensity of combat in the area and the rising presence of Russian reconnaissance and sabotage units there, a statement said.