Russia has denied reports it attempted to spy on hundreds of foreign delegates at a G20 summit using hidden bugging devices in free gifts including teddy bears.

With daily revelations stoking concerns over the extent of covert surveillance by friend and foe alike, the latest reports suggest that Russia hoped to trick G20 delegates into using devices which could feed back sensitive information.

Italy's Corriere della Sera daily has reported that the gifts, which also included USB memory sticks, diaries and mobile phone charging cables, were given to delegates at the St Petersburg summit in September.

The paper said European Council president Herman Van Rompuy asked his staff to check the gifts when he returned to Brussels.

It said that when German security services examined the devices, they discovered they had bugs in them that could steal data from computers and phones.

"These are devices adapted to the clandestine interception of data from computers and mobile telephones," the newspaper quoted a report from the European Council's security office as saying.

Kremlin spokesman Dmitry Peskov has dismissed the claims as a red herring.

"This is undoubtedly nothing but an attempt to shift the focus from issues that truly exist in relations between European capitals and Washington to unsubstantiated, non-existent issues," he was quoted as saying by RIA news agency.

The European Commission has said it is now checking gifts given to delegates, but says so far no bugs have been found.

"Our findings up to now, based upon analysis of hardware and software, have not amounted to any serious security concerns," spokesman Frederic Vincent said.

"However, it is too early to tell whether [the gifts will be found to be] fully clean.

"As a general rule, EU officials when they are travelling are advised not to use external [technical material]."

After initial reports of snooping by the US, sourced to documents provided by former intelligence contractor Edward Snowden, the spying scandal has ballooned out of control, with otherwise close allies such as Washington and Brussels in heated exchanges.

It was reported last week that the US National Security Agency had tapped the mobile phone of German chancellor Angela Merkel for years.

The US has also recently been accused of tapping into millions of phone calls of ordinary citizens in France, Germany and Spain.

Reuters/AFP