The Russian army is intensifying its attacks in eastern Ukraine, military authorities have said, even as the Kremlin’s forces try to check a surprise week-long incursion into Russia by Kyiv’s troops.

Ukraine’s General Staff said on Tuesday that over the previous 24 hours, Russian troops had launched 52 assaults in the area of Pokrovsk, a town in Ukraine’s Donetsk region that is close to the front line. This is roughly double the number of daily attacks there a week ago.

Ukraine’s unexpected charge onto Russian soil that began August 6 has already encompassed some 386 square miles (1,000 square kilometres) of Russian territory, the Ukrainian military claims.

Marine assault team members ride motorcycles towards a Ukrainian position at an undisclosed location
Russian marine assault team members riding motorcycles towards a Ukrainian position at an undisclosed location (Russian Defence Ministry Press Service photo via AP)

The goals of the swift advance into the Kursk region are a closely-guarded military secret.

But analysts say a catalyst may 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.

Still, Ukraine’s cross-border operation — the largest attack on Russia since the Second World War — has rattled the Kremlin. It compelled Russian president Vladimir Putin to convene a meeting on Monday with his top defence officials.

Apparently, Ukraine assembled thousands of troops — some western analysts estimate as many as 10,000 to 12,000 — on the border in recent weeks without Russia noticing or doing anything about it.

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 had seen geolocated footage indicating that Ukrainian forces had advanced up to 15 miles (24km) from the border.

The Russian Defence Ministry appeared to support that claim when it said on Tuesday that it had blocked an attack by units of the 82nd Air Assault Brigade of the Ukrainian armed forces towards Maryinka, which is about that distance from Ukraine.

Russian state television on Tuesday showed residents from evacuated areas queuing 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 the elderly, off buses.

“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,” an elderly man called Mikhail told Russian state television.

“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, according to Mr Putin, but he said that effort would fail.

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

People being evacuated from fighting between Russian and Ukrainian forces in the Kursk region arrive at a temporary residence centre in the Moscow region, Russia
People evacuated from the fighting in the Kursk region arrive at a temporary residence centre in the Moscow region (Ministry of Emergency Situations press service via AP)

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 Defence forces and Chechen units that have been fighting on Russia’s side in the war.

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

Ukraine’s Army General Staff announced on Tuesday that it was establishing of a 12-mile (20km) restricted access zone along the Russian-Ukrainian border in the northeastern Sumy region which borders Kursk.

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