Russia has denied reports it attempted to spy on foreign powers meeting at the G20 summit in St Petersburg earlier this year, denouncing the allegations as a "clear attempt to divert attention" from revelations concerning the United States' National Security Agency.

Two Italian newspapers claimed on Tuesday that USB flash drives and cables to charge mobile phones that were given to delegates – including heads of state – at the September meeting were equipped with technology to retrieve data from computers and telephones.

The St Petersburg summit on 5 and 6 September came at a particularly delicate point in relations between the Kremlin and the White House. Tensions were high over the possibility of military strikes on Syria, as well as over Russia's decision in August to grant asylum to NSA whistleblower Edward Snowden.

The revelations from his dossier of leaked material continue to shake Washington DC and inflame parts of Europe.

According to La Stampa and Corriere della Sera , the first person to raise the alarm over the Russian devices was Herman Van Rompuy, president of the European council, who allegedly went to intelligence services in Brussels and Germany for advice on whether they were what they seemed.

Initial tests carried out by the German secret services reportedly revealed the devices to be equipped with "Trojan horse" programmes "capable of illicitly picking up computer and mobile phone data", according to a warning allegedly sent subsequently to guest countries represented at the G20 summit.

Delegates were urged "to take every possible precaution in the event of these objects having been used and, if they have not been, to hand them over to the security services for further tests", according to Corriere. It said further tests were ongoing.

It was unclear how many delegates and leaders had received the gifts and even less clear whether any of them had actually used the flash drives and chargers, the newspapers wrote.

Dmitri Peskov, spokesman for the Russian president, Vladimir Putin, denied the allegations, saying they were "a clear attempt to divert attention from a problem that really exists: the US's spying, which is now a subject of discussion among European capitals and Washington". He told the Ansa news agency that Russia does not know the sources of the reports, adding that in any case they were baseless.

But the eyebrow-raising claims of what La Stampa termed "Putin's poisoned gift" appeared to have prompted the Italian government to take action on the growing number of allegations regarding covert spying operations. In a statement on Tuesday, it said the country's prime minister, Enrico Letta, had called for the inter-ministerial security committee to meet on Thursday to discuss "questions pertaining to the security of telecommunications in the light of the Datagate [NSA] affair and the revelations on the last G20".

The Italian reports are not the first to have accused a G20 host nation of spying on its guests. In June, the Guardian disclosed that foreign politicians and officials who took part in two such meetings in London in 2009 had their computers monitored and phone calls intercepted on the instructions of their British government hosts.