Russia’s flagship airline, Aeroflot, abruptly canceled 42 flights from Moscow after what was initially described as a technical malfunction — but what has now been confirmed as a devastating cyberattack.

Responsibility for the attack has been claimed by hacker groups Silent Crow and Cyber Partisans BY, who allege they infiltrated Aeroflot’s internal systems more than a year ago. According to their statement, they had been quietly siphoning sensitive flight data while planning a “strategic-level” takedown of the airline’s digital infrastructure.

“Aeroflot’s internal systems have been completely destroyed,” the hackers claimed, adding that recovery could cost tens of millions of dollars. The groups also mocked Russia’s cybersecurity efforts and signed off their message with the slogans “Glory to Ukraine!” and “Long live Belarus!”

While Aeroflot has not confirmed the full extent of the breach, reports in Russian media describe a near-total shutdown. Computers at all Aeroflot offices have stopped working, internal systems are down, and the airline is reportedly unable to refuel aircraft or access flight plans.

“There will be no departures today at all,” one Russian outlet wrote.

This isn’t the first time Russian infrastructure has come under digital fire, but the sheer scale of this attack on a national carrier is unprecedented. Security experts say it could mark a new phase in cyber warfare targeting state-run enterprises.

Meanwhile, tens of thousands of passengers have been left stranded or forced to rebook, as Aeroflot scrambles to assess the damage. No official timeline has been given for the resumption of full operations.