MOSCOW - A hacker attack disrupted Russian flag-carrier Aeroflot's information systems, prompting Moscow's Sheremetyevo Airport to cancel around 60 flights and delay over 80 others, the Russian Prosecutor General's Office said on Monday.

The office issued a statement, stating that the Moscow Interregional Transport Prosecutor's Office has taken control of the situation at Sheremetyevo Airport, adding that "the cause was a failure in Aeroflot's information system due to a hacker attack."

The statement noted that based on the findings of the prosecutors' investigation, a criminal case had been opened concerning unauthorized access to computer information.

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According to Russian newspaper Kommersant, two hacker groups claimed to have carried out a "prolonged and large-scale operation," resulting in the "complete compromise and destruction of Aeroflot's internal IT infrastructure."

The hackers claim they "had been inside Aeroflot's corporate network" for a year, during which they allegedly obtained 12TB of database information and destroyed around 7,000 physical and virtual servers.

"All these resources are now inaccessible or destroyed, and their restoration may require tens of millions of US dollars. The damage is strategic," the newspaper quoted a hacker statement published on its Telegram channel.

Previously, Sheremetyevo Airport had published a guide for passengers affected due to the failure of Aeroflot's information systems, which led to flight rescheduling and cancellations.

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"Sheremetyevo Airport is providing necessary support to the affected airlines for check-in and passenger services. In coordination with air carriers, measures are being taken to stabilize the situation," the airport stated.