Turkish airlines canceled and diverted several flights to Moscow overnight amid widespread Ukrainian drone attacks across Russia and growing security concerns over Russian airspace.

Axar.az reports, citing Turkish media, that Pegasus Airlines canceled 12 flights to and from Moscow’s Vnukovo Airport and diverted a flight from Antalya to Moscow to Istanbul.

Turkish Airlines also canceled four Moscow-related flights, while AJet continued operating its Istanbul-Moscow service.

The disruptions followed Ukrainian President Volodymyr Zelensky’s warning that Russian airspace was becoming increasingly dangerous.