Ukrainian troops have withdrawn from all but a sliver of land in Russia’s Kursk region, according to military analysts and soldiers, as their monthslong campaign to occupy Russian territory appears to be drawing to a close.
At the height of the offensive, Ukrainian forces controlled some 500 square miles of Russian territory. By Sunday, they were clinging to a narrow strip of land along the Russian-Ukrainian border, covering barely 30 square miles, according to Pasi Paroinen, a military analyst with the Finnish-based Black Bird Group.
On Saturday, President Volodymyr Zelensky of Ukraine accused President Vladimir V. Putin of trying to surround Kyiv’s forces in the Kursk region to improve Russia’s position in cease-fire talks, but said that Ukraine’s forces had not been trapped.
Russia’s push to drive Ukrainian forces from all of the territory it seized in the Kursk region last year appeared to accelerate after President Trump froze military aid and intelligence support to Ukraine on March 3. The flow of aid resumed last week when Ukraine agreed to a White House proposal for a 30-day cease-fire.
On Thursday, Mr. Putin said he was open to the proposal but would seek to negotiate over a number of issues.
Here is a look at the Ukrainian incursion — the first on Russian soil since World War II — and how Russian troops fought back.
Why is Kursk important?
Kursk is an area of western Russia that borders the Sumy region of Ukraine. It had long been that Russia might try opening a new front there in its full-scale invasion of Ukraine, which began in February 2022.
But in a move that surprised even its closest allies, and caught Moscow off guard, Ukraine last summer sent its forces pouring across the thinly defended border, opening a new front themselves.
The main objectives, one Ukrainian colonel told The New York Times, were to divert Russian troops from the grueling fighting in the eastern Donbas region of Ukraine, push Moscow’s artillery out of range of the Sumy region and damage Russian morale.
Within weeks of the incursion, Ukraine had established control over a slice of Kursk that its officials said encompassed nearly 500 square miles of farmland and settlements. Though that amounts to barely a sliver of Russia, the largest country in the world, the assault was an embarrassment for Mr. Putin.
The most important town in Kursk that Ukrainian forces seized was Sudzha, an administrative center with a population of around 5,000 people before the incursion.
Analysts said that Ukraine’s offensive was a gamble, stretching its military resources at a time when its troops were struggling to defend a long front line in their own territory.
Mr. Zelensky said that his military did not want to stay on Russian soil indefinitely, and that territory gained in Kursk could be used to strengthen Ukraine’s position in future negotiations with Moscow.
How has Russia responded?
Initially, rather than diverting large numbers of troops to defend Kursk, Mr. Putin said that eastern Ukraine remained Moscow’s main military focus.
But weeks into its incursion in Kursk, Ukraine’s push slowed and its troops began gradually to lose ground as Russian forces deployed there in greater numbers.
Then, in the fall, Russia received a boost from its ally North Korea, which deployed around 11,000 soldiers to Kursk to help Moscow defend it. The deployment at first unnerved Ukraine and its allies. But the North Korean troops suffered wave after wave of heavy losses and, for a time, were withdrawn from the frontline.
In recent weeks, Russian forces, assisted by North Korean fighters, have advanced rapidly in Kursk, using drones and fighter jets to retake much of the territory.
In a sign of renewed military confidence, Mr. Putin visited a command post near the front in Kursk on March 12, the Kremlin said.
Ukraine’s top military commander, Gen. Oleksandr Syrsky, pushed back against the idea of an immediate Ukrainian withdrawal from the area. He said that night that Ukrainian troops would “hold the line in the Kursk region for as long as it remains reasonable and necessary.”
The next day, Russia’s Defense Ministry claimed that its forces had retaken the town of Sudzha. On Saturday morning, Ukraine released a map of the battlefield showing the town outside Ukrainian-controlled territory in the Kursk region.
Russia’s Defense Ministry later said its forces had retaken two villages outside Sudzha.
What is the situation now?
Mr. Putin insisted at a news conference on Friday that Ukrainian forces still fighting in the Kursk region lay down their arms, saying he would spare their lives if they surrendered. He also said Ukrainian forces were encircled there — claims that have been challenged by independent analysts and Ukraine’s military officials have rejected.
Mr. Zelensky, speaking to journalists in Kyiv on Saturday, also called the claim untrue. “There are Ukrainian troops in Kursk region,” he said. “Their encirclement is Putin’s lie.”
Russia’s forces, however, have been trying to cut off and trap Ukrainian troops in the Kursk region by pushing into the neighboring Sumy region in Ukraine, Mr. Zelensky said, adding that Kyiv was countering the threat.
It was not clear how many Ukrainian forces remained in the Kursk region as of Sunday, with many of them having withdrawn in recent weeks.
Ukrainian soldiers at the front described a retreat that was organized in places and chaotic in others, as Russian forces stormed through their lines and forced them back to the small piece of land along the border. It remains unclear how long Ukrainian forces can hold onto that patch.
The continuing fighting in Kursk is now less about holding Russian territory than controlling the best defensive positions to prevent Moscow’s troops from pushing into the Sumy region of Ukraine — and opening a new front in the war.
Maria Varenikova and Anton Troianovski contributed reporting.