Spokesman Dmitry Peskov said the claims were an attempt to shift the focus from real problems affecting European and U.S. relations "to unsubstantiated, non-existent issues," RIA Novosti reported Tuesday.
Peskov's remarks were in response to a report in the Italian newspaper Corriere della Serra that flash drives and mobile phone chargers given to summit attendees secretly gathered information from computers and cellphones on which they were used.
The newspaper said the suspicions came from European Council President Herman Van Rompuy, who asked security experts to analyze the gifts.
A memo sent to G20 members said the devices could be used for spying, the newspaper said.
The report did not rule out the possibility the gifts were intended to "embarrass the Russians."