U.S. President Barack Obama said it during a press conference after today's meeting with German Chancellor Angela Merkel in Berlin, Censor.NET reports.
"There has been a very clear proof that they [the Russians - ed.] have been engaged in cyber attacks. This isn't new, it's not unique to Russia," Obama said.
He pointed out cyber attacks had been committed in a number of states before, although at a lower level, including industrial espionage. According to the president, such actions should be curbed.
Obama said that in a conversation with Russian leader Vladimir Putin before the presidential election in the United States, he made it clear that "although Russia's intelligence gatherings will sometimes take place even if we don't like it, there's a difference between that and meddling with elections or going after private organizations or commercial entities."
He didn't specify if the proof will be made public.
Earlier, Senator Ben Cardin said he was working on a comprehensive bill intended to be a response to recent cyber attacks during the U.S. election campaign, which, according to the American side, were organized by the Russian Federation.
In early October, the United States accused Russia of involvement in hacker attacks on the Democratic Party and promised to retaliate. A representative of the Russian Foreign Ministry said the U.S. lacked evidence.
As NBC further reported, the CIA embarked on developing a plan of cyber attacks against Russia. U.S. Vice President Joe Biden called it a signal to Russian President Vladimir Putin.