It was reported that Pulkovo International received three separate threats between 30 July and 3 August from individuals claiming to have hacked into the airport’s air traffic control systems. The threats were received by post and demanded 200 Bitcoins (c. £980,000). Several days later, on 8 August, the airport’s air traffic control systems froze for 10 minutes, but it is unknown whether this incident was linked to the threats.