July 28 (UPI) -- A cyber attack on Russia's largest airline on Monday saw dozens of canceled flights after a pro-Ukraine team took responsibility for hacking airline computer systems.

Kremlin spokesperson Dmitry Peskov called it "quite alarming" after at least 42 scheduled Aeroflot flights largely domestic in Russia got canceled.

Aeroflot officials gave no specific details or how long it would take to restore its mainframe after officials informed passengers of a "failure" in its tech systems advising service disruptions, but did warn travelers of delays and cancellations.

The airline said its tech teams were "actively working to minimize the impact on flight operations and restore all services to normal as quickly as possible."

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