Romania's "aerial surveillance system" identified "groups of drones launched by the Russian Federation that attacked Ukrainian ports on the Danube," the ministry said. "During the mission, there were no penetrations of aircraft in the national airspace."

The incident highlights the continuing volatility near NATO's eastern border as Russia intensifies aerial attacks on Ukraine.

NATO scrambled two German Eurofighter jets in response to Russian airstrikes near Ukraine's border with Romania overnight into Wednesday. The jets were activated after Russian weapons systems approached Romanian airspace.