A marine drone packed with explosives was destroyed by fighter jets in the Black Sea a few hundred metres from an under-construction gas project.
Two Romanian F-16 planes were sent to respond after the drone was spotted by a commercial ship in the vicinity of the Neptun Deep platform at around 6.30am local time (4.20am UK time).
The platform is part of a project that is set to make Romania the biggest gas producer in the European Union when it comes online next year.
European Commission President Ursula von der Leyen wrote on X: ‘An escalating campaign of threats is underway, unsettling our citizens and seeking to divide our Union.’
Nicușor Dan, Romania’s president, congratulated the jet pilots and coast guard for their response and blamed Russia.
In posts to his social media, he wrote: ‘I strongly condemn the intensification of these types of irresponsible incidents on the part of the Russian Federation.
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‘We remain vigilant alongside NATO allies to defend ourselves and repel such challenges.’
Romanian defence minister Radu Miruţă said he had received confirmation from the Ukrainians that the drone did not originate with them.
He said: ‘In order to protect the lives of the several hundred people who were working on the platform and to secure the critical infrastructure, the decision to destroy the drone was made.’
It comes just four days after a pair of Spanish fighter jets were deployed to shoot down a drone that entered Romanian airspace on Sunday.
According to news agency Reuters, it was the fourth unmanned aircraft to be shot down in Romania – a member of Nato – since the start of this year.
The country shares a 382-mile land border with Ukraine, and its proximity has meant it is occasionally impacted directly.
In May, a drone from Russia hit a block of flats in the eastern town of Galați, which is close to the border with Ukraine.
Two people were injured in the incident, which also started a fire in the building, prompting an evacuation.
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