Ukrainian drones have struck an oil refinery and a fuel depot in Russian border regions, officials said, as part of Kyiv’s effort to disrupt the Kremlin’s war machine.

An overnight drone attack hit the Novoshakhtinsk refinery in the Rostov region and started a fire, regional governor Vasily Golubev said. Firefighters had to pull out briefly because of a second attack, he added.

He said there were no casualties.

In Belgorod, a drone hit an oil depot overnight, governor Vyacheslav Gladkov said, causing an explosion and a fire in one of the oil reservoirs. The blaze was quickly extinguished and there were no casualties, the governor said.

D-Day 80th anniversary
French President Emmanuel Macron with wife Brigitte and King Charles III and Queen Camilla at a D-Day commemoration in Normandy (Jane Barlow/PA)

The assault came as Ukrainian President Volodymyr Zelensky Zelensky was due to join world leaders at D-Day commemorations in France, as he seeks further western support in Europe’s biggest conflict since the Second World War.

Refineries, fuel depots and oil terminals have been targets of increasingly sophisticated Ukrainian drone attacks which have reached deep into Russia. The attacks deny Moscow revenue and western sanctions have added to the pressure on Russia’s energy sector.

Russia, meanwhile, has been attacking Ukraine’s energy infrastructure and causing widespread power outages. The apparent goal is to sap public morale and affect military manufacturing plants.

Mr Zelensky’s trip to France came a day after Russian President Vladimir Putin warned that Moscow could provide long-range weapons to other countries so they could strike western targets.

That threat came after Nato allies said they would allow Ukraine to use weapons they deliver to Kyiv to attack Russian territory.

Dmitry Medvedev watches an anti-drone rifle demonstration
Dmitry Medvedev watches an anti-drone rifle demonstration (Ekaterina Shtukina/Sputnik/AP)

Ukraine’s army is fighting to hold back a Russian push in eastern areas that seeks to exploit Kyiv’s shortages of ammunition and troops along the 620-mile front line after more than two years of war.

Dmitry Medvedev, deputy head of Russia’s Security Council, said Mr Putin’s comments on Wednesday in St Petersburg amounted to “a quite significant shift in our foreign policy”.

“Let the US and its allies feel the impact of direct use of Russian weapons by others,” he said.

Mr Putin deliberately did not name potential recipient countries of Russian weapons, Mr Medvedev said. They could go to anyone who considers the US and its allies their enemies, he added.

Kremlin spokesman Dmitry Peskov said the use of western weapons against Russia “can’t be left without consequences, and those consequences will certainly follow”.

Mr Putin claimed that using some western-supplied weapons involves military personnel of those countries controlling the missiles and selecting targets, so Moscow could take “asymmetrical” steps elsewhere in the world.

Joe Biden countered Mr Putin’s threat with an insistence that Washington has imposed restrictions on how Ukraine can use US-supplied weapons inside Russia.

Joe Biden
President Joe Biden arrives in France for D-Day commemorations (Julien de Rosa/AP)

“We’re not talking about giving (Ukraine) weapons to strike Moscow, to strike the Kremlin,” the US president told ABC News.

Ukraine has received authorisation to use the weapons “just across the border where they’re receiving significant fire from conventional weapons used by the Russians to go into Ukraine to kill Ukrainians”, he added.

Mr Biden admitted he was “concerned” by Mr Putin’s behaviour and called him “a dictator”.

The US military said it does not control the missiles it provides to Ukraine or the targets, and Nato secretary-general Jens Stoltenberg said the alliance has no plans to deploy forces to Ukraine.

“We are focusing on how we can establish a stronger framework for our support, with an institutionalised framework for the support to Ukraine and how to establish an agreed long-term financial commitment to ensure that we stand by Ukraine for as long as it takes,” he said.