Romania has become the most recent NATO country to confirm a drone violation of its airspace on Saturday, coinciding with Poland dispatching aircraft due to new Russian drone attacks near the Ukrainian border.

Ukrainian President Volodymyr Zelensky cautioned that Russia is intentionally broadening its drone operations, urging the West to implement stricter sanctions and enhance defense collaboration.

In Washington, US President Donald Trump expressed his readiness to introduce substantial sanctions against Russia, contingent on all NATO countries taking similar steps and halting purchases of Russian oil.

On Saturday, Romania’s defense ministry reported that its airspace was penetrated by a drone amidst a Russian assault on infrastructure in Ukraine.

The country scrambled two F-16 fighter jets late on Saturday to monitor the situation following the strikes, said a defence ministry statement.

The military jets identified a drone within Romania’s airspace and monitored it until it vanished from radar close to the Romanian village of Chilia Veche, they stated.

Also Saturday, Poland said it and its NATO allies had deployed helicopters and aircraft as Russian drones struck Ukraine not far from its border.

Because of the drone threat, ‘Polish and allied aircraft are operating in our airspace, and ground-based air defence and radar reconnaissance systems have reached their highest level of alert,’ the country’s military command posted in a statement on X.

Later Saturday, Polish Prime Minister Donald Tusk announced that the high alert had been lifted, while cautioning: ‘We remain vigilant.’

Poland and its fellow NATO countries have been on their guard since Warsaw said nearly 20 Russian drones entered its airspace overnight Tuesday to Wednesday.

While Russia denies targeting Poland, several European countries including France, Germany and Sweden have stepped up their support for defending Polish airspace in response.

‘Today, Romania scrambled combat aircraft because of a Russian drone in its airspace,’ said Ukrainian President Volodymyr Zelensky.

‘Also today, Poland responded militarily to the threat of Russian attack drones,’ which had also been active in different regions of Ukraine all day, he added.

The Russian military knows exactly where their drones are headed and how long they can operate in the air,’ said Zelensky.

The latest drone incursions were ‘an obvious expansion of the war by Russia’, he added.

What was required in response were fresh sanctions against Russia and a collective defence system, Zelensky argued.

‘Do not wait for dozens of ‘shaheds’ and ballistic missiles before finally making decisions,’ he warned, referring to the Iranian-designed Shahed drones Russia is using.

US Secretary of State Marco Rubio on Saturday expressed concern at the Russian drone incursion into Polish airspace earlier in the week.

If it turned out to have been deliberate, ‘then obviously it will be… highly escalatory,’ he told reporters in Washington.

Trump’s suggestion on Thursday that the incident might have happened by ‘mistake’, was quickly dismissed by Tusk.

On Saturday, Trump returned to the issue of sanctions against Russia, putting the ball back in the court of his NATO allies.

‘I am ready to do major Sanctions on Russia when all NATO Nations have agreed, and started, to do the same thing, and when all NATO Nations STOP BUYING OIL FROM RUSSIA,’ he said in a post on his Truth Social platform.

Trump has repeatedly threatened sanctions against Russia without following through.

In Russia, an official reported that a Ukrainian drone had hit one of its largest oil refining complexes, 1,400 kilometres (870 miles) from the front line in Ukraine.

The drone had sparked a fire and caused minor damage at the complex, which belongs to Russian oil company Bashneft, and lies on the outskirts of the central Russian city of Ufa.

A source in Ukraine’s GUR military intelligence agency claimed responsibility for the attack.

Since Moscow launched its full-scale military offensive in Ukraine in February 2022, Kyiv has responded with attacks on Russian refineries in an attempt to curb the Kremlin’s ability to fund the conflict through its fossil fuel industry.