Russian hackers attacked a satellite internet network in Ukraine causing thousands of modems to go offline at the beginning of the war in Ukraine, Britain and the European Union said on Tuesday.

The digital assault against Viasat’s KA-SAT networkin late February took place just as Russian armour pushed intoUkraine and helped facilitate President Vladimir Putin’sinvasion of the country, the Council of the EU said in astatement.

“This cyberattack had a significant impact causingindiscriminate communication outages and disruptions acrossseveral public authorities, businesses and users in Ukraine, aswell as affecting several EU Member States,” the statement said.

“This unacceptable cyberattack is yet another example ofRussia’s continued pattern of irresponsible behaviour incyberspace, which also formed an integral part of its illegaland unjustified invasion of Ukraine,” it added.

The remote sabotage caused a “huge loss in communications inthe very beginning of war,” Ukrainian cybersecurity officialVictor Zhora said in March.

Russia routinely denies it carries out offensive cyberoperations. The Kremlin did not immediately respond to a requestfrom Reuters for comment.

Western intelligence agencies, including the U.S. NationalSecurity Agency, French government cybersecurity organisationANSSI, and Ukrainian intelligence were investigating Russia’spotential role in the attack in the days after it, Reutersreported at the time.

A British Foreign Office statement quoted Foreign SecretaryLiz Truss as saying the cyberattack was a “deliberate andmalicious attack by Russia against Ukraine”.

Russia’s primary target in the attack was the Ukrainianmilitary, but it also disrupted wind farms and internet users incentral Europe, the statement said, citing Britain’s NationalCyber Security Centre (NCSC).