Russia, Turkey and South Africa have expressed outrage after revelations that Britain and the United States spied on foreign delegates at G20 meetings in London in 2009. File photo: Supplied

London - Russia, Turkey and South Africa expressed outrage on Monday after revelations that Britain and the United States spied on foreign delegates at G20 meetings in London in 2009.

The Turkish government summoned Britain's charge d'affaires to explain a newspaper report claiming that London placed Finance Minister Mehmet Simsek under surveillance during the talks.

Moscow, meanwhile, expressed concern that US spies had intercepted communications made by then-president Dmitry Medvedev while he was in Britain, and some Russian lawmakers warned it could harm US-Russian ties.

British Prime Minister David Cameron said he would not comment on intelligence matters, but the revelations were likely to be embarrassing as he hosts G8 leaders at a summit in Northern Ireland.

The claims are based on documents leaked by former US spy Edward Snowden, who has already invoked the ire of Washington by lifting the lid last week on a massive US Internet surveillance system.

According to The Guardian newspaper, Britain's GCHQ electronic eavesdropping agency used “ground-breaking intelligence capabilities” to monitor communications at two G20 meetings in April and September 2009.

Delegates were allegedly tricked into using specially prepared Internet cafes which allowed British spies to intercept and monitor email messages and phone calls through BlackBerry devices.

GCHQ was also able to track when delegates were contacting each other and the agency targeted certain officials, including the finance minister of Nato ally Turkey.

Ankara responded with outrage, contacting the British ambassador and summoning the deputy head of mission to demand an explanation, a foreign ministry diplomat said.

Earlier, the ministry said that if the report was true, “such an action by an ally country is unacceptable”.

“This will constitute a scandal in terms of relations between the two countries if any truth is found in the allegations,” it said.

The British Foreign Office confirmed that its deputy head of mission had met Turkey's director general for intelligence and security at the foreign ministry in Ankara, but gave no details.

Officials travelling to Northern Ireland with Russian President Vladimir Putin meanwhile expressed concern over claims that US agents spied on his predecessor while he was in London.

“As a country which takes steps to protect its own information, we are worried,” said Russia's G8 negotiator Alexei Kvasov.

The reaction in Moscow was less diplomatic.

“It's a scandal!” fumed Alexei Pushkov, the head of the lower house of Parliament's foreign affairs committee, on Twitter.

Senator Igor Morozov, a member of the international affairs committee of the upper house of Parliament, said it risked hurting ties with Washington.

“In this situation how can we trust the current announcements of US President Barack Obama, who is talking about a new 'reset' (of relations)?” he told the RIA Novosti news agency.

Cameron earlier told Sky News television: “We never comment on security or intelligence issues, and I am not about to start now.”

The Guardian said that South African computers were also singled out for special attention, prompting Pretoria to warn against the abuse of privacy and “basic human rights”.

“We have solid, strong and cordial relations with the United Kingdom and would call on their government to investigate this matter fully with a view to take strong and visible action against any perpetrators,” the foreign ministry said.

The leaked documents suggest that orders to gather intelligence on G20 delegates came from a senior level within the government of Britain's then-prime minister Gordon Brown.

A briefing paper prepared for GCHQ director Iain Lobban, dated January 9, 2009, said the agency's remit was “to ensure that intelligence relevant to Her Majesty's government's desired outcomes for its presidency of the G20 reaches customers at the right time and in a form which allows them to make full use of it”.

Snowden, currently in hiding in Hong Kong, has vowed to fight any attempt by the United States to extradite him, as it pursues a criminal investigation into the Internet surveillance leaks.

In a live question-and-answer session on The Guardian's website on Monday, he said there were more revelations to come about the US National Security Agency's access to Internet data. - Sapa-AFP