Romania’s president has accused Russia of deploying a marine drone that its military destroyed on Thursday after it was spotted close to a major natural gas development.

The development marks yet another incident in which Russia’s war in Ukraine has potentially spilled beyond the country’s borders, underscoring risk to critical infrastructure.

In a series of Facebook posts, Romanian defense minister Radu-Dinel Miruţă said F-16 fighter jets destroyed a marine drone in the vicinity of the Neptun Deep gas project in the Black Sea on Thursday.

Once developed, Neptun Deep will make Romania the largest natural gas producer in the European Union. Located around 99 miles off the coast, the platform is expected to begin producing gas in 2027.

European energy prices rose drastically in the wake of Russia’s full-scale invasion of Ukraine in 2022, as Western governments slapped Moscow with sanctions and looked for alternative sources of oil and gas.

Miruţă said Thursday that the Romanian Coast Guard reported the presence of the drone a few hundred meters from Neptun Deep’s gas extraction operations on Thursday morning, 80 miles east of the Romanian city of Constanța.

Romania’s defense ministry then requested NATO authorization to “take charge of the situation,” he said.

“Following an assessment and in coordination with the President of Romania, the decision was made to destroy the drone in order to protect the lives of the hundreds of personnel working on the platform and to safeguard critical infrastructure,” Miruţă added.

“To ensure a rapid response, two Romanian F-16 fighter jets were scrambled with orders to engage. The drone was safely destroyed.”

The operation was “an action against time,” Romanian President Nicușor Dan said in a post on X. He added that the drone had come from Russia.

“I strongly condemn the intensification of these types of irresponsible incidents on the part of the Russian Federation,” he said. “We remain vigilant alongside NATO allies to defend ourselves and repel such challenges.”

CNBC reached out to the Russian government for comment.

Romania shares a border with Ukraine, with Russia lying across the Black Sea. Miruţă said Romanian officials had confirmed the drone was not of Ukrainian origin. Data indicated that only a single drone was involved in the incident, according to Romanian investigations.

A NATO spokesperson told CNBC the military alliance was “aware that two Romanian Air Force F-16 aircraft were scrambled in response to a maritime drone detected in Romania’s Exclusive Economic Zone in the Black Sea.”

“One of the aircraft successfully engaged the drone, demonstrating continued readiness to respond to any potential threat,” they said.

A series of Russian aircraft have breached Romanian airspace in recent weeks, with Romania’s Air Force shooting a drone down in late July.

Romania’s Dan said at the time that his country and its allies treated such incidents with “the utmost seriousness,” labeling the airspace incursion “inadmissible and intolerable.”

In May, an apartment block in Galați – a city near Romania’s border with Ukraine – was hit by a Russian drone.