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.

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.

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.