The Ukrainian military has denied involvement in yesterday’s cross-border raids by pro-Kyiv militias.

The paramilitary groups are “independent organisations” of Russian nationals, Andrii Yusovhe, a representative of Ukraine’s intelligence agency, was quoted as saying by the BBC.

The Russian defence ministry claims its forces killed 234 fighters during a major cross-border incursion yesterday from Ukraine.

The reports of border fighting earlier yesterday were murky, and it was impossible to ascertain with any certainty what was unfolding in Russia’s Kursk and Belgorod regions.

Cross-border attacks in the area have occurred sporadically since the war began and have been the subject of claims and counterclaims, as well as disinformation and propaganda.

Soldiers who Kyiv officials say are Russian volunteers fighting for Ukraine claimed to have crossed the border.

The Freedom of Russia Legion, the Russian Volunteer Corps and the Siberian Battalion released statements and videos on social media claiming to show them on Russian territory.

They said they wanted “a Russia liberated from Putin’s dictatorship”.

The authenticity of the videos could not be independently verified.

In a statement, the Russian defence ministry blamed the attack on the “Kyiv regime” and “Ukraine’s terrorist formations”, insisting that the Russian military and border forces were able to stop the attackers and avert a cross-border raid.

It also claimed the attackers lost seven tanks and five armoured vehicles.

Late Russian opposition leader Alexei Navalny’s long-time aide Leonid Volkov was assaulted with a hammer in the Lithuanian capitol Vilnius on Tuesday, former Navalny spokesperson Kira Yarmysh said.

“Volkov has just been attacked outside his house. Someone broke a car window and sprayed tear gas in his eyes, after which the attacker started hitting Leonid with a hammer,” she wrote on social media website X.

She posted images showing Volkov with a bruise on his forehead, blood coming from a leg wound, and a vehicle with damage to the driver’s door and window.

Lithuania’s foreign affairs minister Gabrielius Landsbergis, who also leads Homeland Union, the ruling party, called the assault “shocking”.

“Perpetrators will have to answer for their crime”, he wrote on X.

Lithuanian police said they had been informed a man was beaten outside his home, and were investigating.

North Korea has not asked Moscow for any help with its nuclear programme, claims Russian president Vladimir Putin.

“The Democratic People’s Republic of Korea has its own nuclear umbrella,” he said. “They didn’t ask us for anything.”

Pyongyang is widely believed to be providing Moscow with arms supplies in exchange for Russian support with its struggling satellite launch programme.

Strategic ties between the two countries appear to have grown stronger since Kim Jong-un met his Russian counterpart at Vostochny Cosmodrome in September last year.

Finland and Sweden’s entry into Nato is “a meaningless step”, said Russian president Vladimir Putin. He warned that Russia will deploy troops and systems of destruction to the Finnish border after Finland joins the alliance.

“This is an absolutely meaningless step (for Finland and Sweden) from the point of view of ensuring their own national interests,” Mr Putin said.

“We didn’t have troops there (at the Finnish border), now they will be there. There were no systems of destruction there, now they will appear.”

Vladimir Putin, in a wide-ranging interview with RIA and the Rossiya-1 state television channel, has said that Russia is ready - from a military-technical point of view - for a nuclear war, but that for now not “everything is rushing to it”.

The Russian president also reiterated the Kremlin’s position that Russia could restart explosive nuclear tests, but only if the US does so first.

Russia pulled out of an important nuclear non-proliferation treaty in October last year, which was followed just hours later by the US conducting a sub-critical test at a nuclear facility in Nevada.

The US has not conducted an explosive nuclear test since 1992 and says it has no plans to abandon a moratorium on such activity.

Elsewhere in the RIA interview published on Wednesday, Vladimir Putin said that if US troops appear in Ukraine, Russia will treat them as “interventionists”.

The comments came as the Joe Biden administration on Tuesday announced it would be sending an additional $300m in security assistance to Ukraine.

And it comes amid controversy among Kyiv’s European allies after leaked remarks by German military officers suggested British troops were on the ground in Ukraine helping local forces aim long-range missiles at Russia. The UK has denied having any direct involvement in fighting.

President Vladimir Putin said in remarks published on Wednesday that Russia does not interfere in any elections and it will work with any elected US leader.

“We do not interfere in any way in any elections,” Mr Putin told RIA state news agency and Rossiya-1 state television in a wide-ranging interview. “And, as I have said many times, we will work with any leader who is trusted by the American people, the American voter.”

Mr Putin also said that Donald Trump, when he was president, scolded him for “sympathising” with now president Joe Biden.

Ukraine launched drone attacks on several Russian regions for the second night in row, officials said on Wednesday, causing damage to a gas supply line and cutting off power to some villages in the Belgorod region.

“No one was injured,” Vyacheslav Gladkov, the governor of the Belgorod region that borders Ukraine said on the Telegram messaging app.

Four Ukraine-launched drones were destroyed over the region and falling debris caused damage to a gas supply line in one village and cut off electricity to a couple of others, Gladkov added. Some houses were damaged in the town of Gubkin.

He also said the town of Shebekino came under fire from Ukrainian forces, injuring one man and damaging a power line in the town and nearby villages.

Roman Starovoit, governor of the Kursk oblast north of Belgorod, which also borders Ukraine to its west, said air defence systems destroyed four Ukraine-launched drones.

He did not provide further detail on any potential damage.

The governor of the Voronezh region in Russia’s south said air defence systems were engaged several times in the region in repelling a drone attack by Ukraine, but there was no “consequences for civilian objects” as a result of the attack.

On Tuesday, Ukraine pounded targets in Russia with dozens of drones and rockets in an attack that inflicted serious damage on a major oil refinery and sought to pierce the land borders of the world’s biggest nuclear power with armed proxies.