Romania says a Russian drone has entered its airspace — the second NATO country to report such an incursion in a week — as tensions rise along the alliance’s eastern flank.

The Romanian Defence Ministry said two F-16 fighter jets detected the drone on Saturday while monitoring Russian air attacks on Ukraine’s Danube region. The aircraft identified the drone, believed to be a Geran (the Russian name for the Iranian-designed Shahed-136), about 20km south-west of the village of Chilia Veche before it disappeared from radar.

Officials said the drone did not fly over populated areas or pose an imminent threat. Under a new Romanian law passed this summer, pilots were authorised to shoot down hostile drones but chose not to after “assessing collateral risks”.

Bucharest has summoned the Russian ambassador to protest the incident. EU foreign policy chief Kaja Kallas condemned the drone’s flight as “yet another unacceptable breach of an EU member state’s sovereignty”.

Ukrainian President Volodymyr Zelensky said the incursion “could not be a mistake” and amounted to an expansion of the war by Russia. Moscow has not commented on Romania’s claims.

On Wednesday, Poland said it had shot down at least three Russian drones over its territory. Prime Minister Donald Tusk announced heightened air-defence readiness and “preventive operations” by Polish and allied aircraft.

The latest incidents underline mounting concern in Eastern Europe over Russian military activity spilling across borders. In response, the Czech Republic has deployed a special operations helicopter unit to Poland, while NATO states continue to reinforce their eastern defences.

Russia launched its full-scale invasion of Ukraine in February 2022 and has intensified attacks on Ukrainian infrastructure in recent weeks.