Russia  on Wednesday said it was continuing to battle Ukrainian troops that crossed into the border region of Kursk a day earlier, with a state of emergency declared by the regional governor and security tightened around a nearby nuclear power plant.

"To eliminate the consequences of enemy forces coming into the region, I took the decision to introduce a state of emergency in the Kursk region from 7 August," said Kursk's acting Governor Alexei Smirnov on Wednesday evening.

In a video conference, Russia's Chief of the General Staff Valery Gerasimov told President Vladimir Putin that "a unit of Ukraine's armed forces numbering up to 1,000 people went on the offensive" in the Kursk region on Tuesday morning.

The Russian Defense Ministry said on social media that "the enemy's movement further into Russian territory has been prevented" but that "the operation for the destruction of Ukrainian army units is continuing."

Putin: 'Large-scale provocation'

Putin said Ukraine was carrying out a "large-scale provocation" in the region, from which several thousand people have reportedly been evacuated.

"In the last 24 hours, our region has been heroically resisting attacks," Governor Smirnov said, also urging local residents to donate blood.

Russia said Ukrainian troops, supported by tanks and armoured vehicles, had launched an assault on Russian border forces in the Kursk settlements of Nikolayevo-Daryino and Oleshnya, two towns just across the border with Ukraine's Sumy region.

At least five people have been killed and 24 others injured, according to Russian authorities.

The troops reportedly advanced as far as the Russian town of Sudzha, home to the last operational trans-shipment point for Russian gas exports to Europe via Ukraine. 

Russian National Guard deployed to nuclear power plant

On Wednesday evening, Russia deployed National Guard troops to protect the Kursk nuclear power plant, which is just 60 kilometers (40 miles) from the Ukrainian border. The power plant has four reactor blocks and a total output of almost two gigawatts, feeding the grid for Kursk and 19 other regions.

Additional forces have also been deployed to combat sabotage and reconnaissance troops in the Kursk and Belgorod regions, the national guard announced.

On Tuesday, the Russian Defense Ministry said that "border defense troops, together with military units of the FSB border force" were "repelling attacks and inflicting fire damage on the enemy."

No comment from Zelenskyy or Washington

Ukraine has not explicitly said it is carrying out a fresh offensive on the Kursk region. Ukraine's general staff, however, has mentioned Russian attacks on border villages in Ukraine.

In his daily televised remarks on Wednesday evening, Ukrainian President Volodymyr Zelenskyy made no reference to the reported Kursk incursion, but did say: "The more pressure put on Russia, the aggressor which brought war to Ukraine, the closer we come to peace. A just peace [achieved] through just strength."

Ukraine on Wednesday afternoon also ordered the evacuation of 23 settlements in the Sumy border region, affecting around 6,000 people. 

Asked about the reported Ukrainian raid, US National Security spokesman John Kirby said Washington would be "reaching out to our Ukrainian counterparts to get a little bit better understanding."

"I'll let the Ukrainians speak to their operations, one way or the other, that's most appropriate. We're going to stay focused on making sure they have what they need to defend themselves," Kirby added.

Is fighting around Russia's border regions common? 

Russia launched its invasion of Ukraine in February 2022. There have been several incursions into Russian territory since then.

In May 2023, the Ukrainian-based Freedom of Russia Legion made up of Russian citizens conducted raids into the Belgorod region of Russia. The Russian Volunteer Corps unit, which is also composed of Russian nationals, helped out in those border raids. 

In March 2023, the Russian Volunteer Corps said they were responsible for a raid in the Russian border region of Bryansk.   

Neither the Freedom of Russia Legion nor the Russian Volunteers Corps have commented on reported border attacks on the Russian Kursk region.   

mf/wd (Reuters, AP, AFP)