Ukrainian President Volodymyr Zelenskyy said Moscow's attacks were expanding into new countries and directions. "They use every tool: from interference in political processes, as in Romania and Moldova, to violations of airspace, as in Poland, Romania, and now Estonia," he said in a post on X.

"This is a systematic Russian campaign directed against Europe, against NATO, against the West. And it requires a systemic response," Zelenskyy said.

Earlier this month, Poland reported more than a dozen drones crossed its border overnight, with some heading toward the strategic hub of Rzeszów. Polish forces, backed by NATO allies, shot down several drones and later also invoked NATO's Article 4. Warsaw called the incident a deliberate Russian provocation.

On Sept. 12, NATO Secretary-General Mark Rutte announced the launch of the “Eastern Sentry” mission to bolster defenses on the alliance’s eastern flank in response to the Russian drone incursion.

Romania has also faced repeated violations, including a drone tracked for nearly 50 minutes in its airspace in mid-September. Fragments from earlier Russian attacks in Ukraine have repeatedly landed on Romanian territory. 

Announcing a new round of EU sanctions on Russian energy and financial transactions on Friday, European Commission President Ursula von der Leyen deplored that in recent days "Russian drones have violated our union's airspace, both in Poland and in Romania."