Romania scrambled fighter jets on Saturday when a drone breached the country’s airspace during a Russian attack on Ukrainian infrastructure near the border, the defence ministry said.

Defence minister Ionut Mosteanu said the F-16 pilots came close to taking down the drone as it was flying very low before it left national airspace toward Ukraine.

A threat of drone strikes also prompted Poland to deploy aircraft and close an airport in the eastern city of Lublin on Saturday, three days after it shot down Russian drones in its airspace with the backing of aircraft from its Nato allies.

Romania, a European Union and Nato state that shares a 650km (400-mile) border with Ukraine, has had Russian drone fragments fall on to its territory repeatedly since Russia began waging war on its neighbour.

On Saturday, it scrambled two F-16 fighter jets and later two Eurofighters – part of German air policing missions in Romania – and warned citizens in the southeastern county of Tulcea near the Danube and its Ukrainian border to take cover, the defence ministry said in a statement.

It added the jets detected a drone in national airspace, which they followed until it dropped off the radar 20km southwest of the village of Chilia Veche.

Mr Mosteanu said helicopters will survey the area near the border to look for potential drone parts, “but all information at this moment indicates the drone exited airspace to Ukraine”.

Ukrainian president Volodymyr Zelenskiy said on X that data showed the drone breached about 10km into Romanian territory and operated in Nato airspace for around 50 minutes.

Romanian soldiers build a bomb shelter in the village of Plauru, the Danube Delta, an area where drone fragments have been found. Photograph: MIHAI BARBU/AFP via Getty ImagesRomanian soldiers build a bomb shelter in the village of Plauru, the Danube Delta, an area where drone fragments have been found. Photograph: MIHAI BARBU/AFP via Getty Images

“It is an obvious expansion of the war by Russia – and this is exactly how they act,” he said. “Sanctions against Russia are needed. Tariffs against Russian trade are needed. Collective defence is needed.”

Nato announced plans to beef up the defence of Europe’s eastern flank on Friday, after Poland shot down drones that had violated its airspace, the first known shots fired by a member of the western alliance during Russia’s war in Ukraine.

Romanian lawmakers approved a law earlier this year enabling the army to shoot down drones illegally breaching Romanian airspace during peacetime, based on threat levels and risks to human life and property, but the Bill does not yet have all enforcement rules approved.

Elsewhere, Ukrainian drones attacked the Kirishi oil refinery in Russia’s northwest, one of the country’s biggest, sparking a fire when debris fell from a shot-down drone, Russian officials said on Sunday.

Surgutneftegaz’s Kirishinefteorgsintez refinery, one of the top two refineries in Russia, was attacked by Ukrainian drones, Russian officials said.

Alexander Drozdenko, the governor of the Leningrad region, said that three drones were destroyed in the Kirishi area and that a fire sparked by falling debris had been put out. He said no one was injured.

Ukraine’s drone command confirmed it attacked the refinery and said it had “carried out a successful strike”.

Reuters was unable to immediately verify the scale of the damage, if any, to the refinery. – Reuters