US Secretary of State Mike Pompeo said last night that Russia was very likely behind a major cyber attack that hit the US and targets in other countries.
"It was a very large undertaking, I think we can now say quite clearly that the Russians engaged in that activity," Pompeo said on "The Mark Levin Show" with political commentator Mark Levin.
Pompeo assessed that it was a large-scale operation that consisted of using software to break into the "systems of the US government".
Russia has vigorously denied involvement in the case.
"Russia does not conduct offensive operations in cyberspace," the Russian embassy in Washington said.
The scope of cyber-attacks is constantly expanding as new victims outside the US are discovered and fears of espionage risks are revived.
Republican Senator Marco Rubio, chairman of the Senate Intelligence Committee, said yesterday that this is a major cyber attack that is probably still ongoing.
The American government only discovered the existence of that cyber attack last Sunday, which began in March, if not earlier, France Press reports.
US authorities expressed concern on Thursday about intrusions into computer systems in the US and around the world that officials suspect were carried out by Russian hackers, and the Cybersecurity Agency warned of a "serious" risk to government and private networks.
The Cyber Security and Infrastructure Agency (CISA) did not say which agencies or infrastructure were breached or what information was taken in the hack, which was said to have started in March.
The agency stated that it was difficult to detect the intrusion and that it will not be easy to remove the software that was injected into the computer systems.
Microsoft said Thursday it had notified more than 40 of its customers affected by the software used by the hackers, saying it could give them unfettered access to victims' networks.
"About 80 percent of those clients are located in the US, but through our work we have also identified victims in several other countries at this stage," said Microsoft President Brad Smith, on the company's blog.
Victims have been identified in Canada, Mexico, Belgium, Spain, Great Britain, Israel and the United Arab Emirates.
Smith said it was certain that the number of victims and affected countries would continue to rise, creating "serious technological vulnerabilities for the US and the world".
Smith said it was "not ordinary espionage even for the electronic age".
Although Senator Rubio assessed that some foreign force was behind that "patient, sophisticated and well-financed act", he did not go further to express his doubt as to which country it was.
However, the suspicions of cyber security experts are directed towards Moscow.
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