Italian media said that leaders of the world’s most powerful nations, including Barack Obama, were given welcome packs last month that included USB flash- drives and universal mobile phone battery chargers — which were actually spying devices which allowed sensitive documents stored on laptops to be accessed.

The devices were “a poisoned gift” from Vladimir Putin, claimed La Stampa, the Turin-based daily. “They were Trojan horses designed to obtain information from computers and cell phones,” the paper said.

Vladimir Putin’s spokes- person Dmitri Peskov denied the allegations.

“This is a clear attempt to divert attention from a real problem: the US spying activities,” Peskov said.

The EU Council refused to comment.

Italian media reported that EU Council president Herman van Rompuy became suspicious and had security experts from Germany’s intelligence services conduct tests. Those tests revealed the gifts were bugging devices.

“The USB flash-drives and the power cables are suitable for use as secret tapping devices able to gather computer and mobile phones data,” Il Corriere della Sera daily newspaper quoted the report as saying.

Peskov said the report was an attempt to divert attention away from NSA whistleblower Edward Snowden and America’s spying programme.

“We don’t know what sources of information are involved, but it is definitely nothing other than an attempt to switch attention from the problems that really exist, which dominate the agenda between the European capitals and Washington, to problems that are ephemeral and non-existent,” he said.

Van Rompuy’s office said it would not comment on the issue, as did a spokesman for European Commission president Jose Manuel Barroso, who was also present at the St Petersburg talks.

Downing Street said David Cameron was not given one of the USB sticks, but conceded officials in the British delegation may have received them.

The British prime minister’s official spokesman said: “My understanding is that the Prime Minister didn’t receive a USB drive because I think they were a gift for delegates, not for leaders.”

Meanwhile, faced with a flood of revelations about US spying, President Barack Obama and key lawmakers say it’s time to look closely at surveillance programmes that may have gone too far.

The White House is considering ending eavesdropping on friendly foreign leaders, a senior administration official said.

The administration is trying to undo damage from the months-long spying scandal — including the most recent disclosure that the National Security Agency monitored the communications of German chancellor Angela Merkel.

A final decision about listening in on allies has not been made, the official said.

The White House also faces complaints at home about the NSA collecting millions of Americans’ phone records and sweeping up internet traffic and email.

The House Intelligence Committee was to examine tightening the rules on those anti-terror programmes in a hearing later last night.

Asked about the reports of eavesdropping on world leaders, President Obama said in a television interview that the US government is conducting “a complete review of how our intelligence operates outside the country”.

Obama declined to discuss specifics or say when he learned about the spying operations.

“What we’ve seen over the last several years is their capacities continue to develop and expand, and that’s why I’m initiating now a review to make sure that what they’re able to do doesn’t necessarily mean what they should be doing,” he said.