The Russian authorities deny allegations from Microsoft that hackers linked to Russia's government tried to target the websites of two right-wing U.S. think-tanks, the Interfax news agency reported on Tuesday.
The software giant said it had thwarted the Russia-linked attempts last week, which it suggested showed Moscow was broadening its attacks in the build-up to November elections.
Interfax cited an unnamed Russian diplomatic source on Tuesday as describing Microsoft's allegations as part of a political game.
"Microsoft is playing political games," it cited the source as saying. "The (mid-term U.S.) elections have not happened yet, but there are already allegations."
Microsoft was acting like a prosecutor rather than a private company, Interfax quoted the source as adding.