Updated

The European Union was one of the "targets" of Washington's huge Internet spy programme, with bugs hidden in EU offices in Brussels and the United States, German weekly Der Spiegel said in an edition to be published Sunday.

The magazine said the claims were based on confidential documents it was partly able to consult through US intelligence leaker Edward Snowden, who this month revealed the existence of the so-called PRISM programme operated by the US National Security Agency (NSA).

A document dated September 2010 and classed as "strictly confidential" describes how the secretive NSA kept tabs on the European Union's diplomatic mission in Washington, the magazine said.

Microphones were installed in the building and the computer network had been infiltrated, giving the agency access to emails and internal documents.

The EU representation at the United Nations was subject to similar surveillance, Der Spiegel said, adding that the leaked documents explicitly referred to the Europeans as "targets".

The spying extended to the 27-member bloc's Brussels headquarters, Der Spiegel said, referring to an incident "more than five years ago" when EU security experts discovered telephone and online bugging devices at the Justus Lipsius building.

In 2003, the EU announced it had discovered phone taps in the building targeting the offices of several countries, including Germany, Britain and France.

But it was not immediately clear if Der Spiegel was referring to this case.

In reactions published on the magazine's website, European Parliament chief Martin Schulz said more information was needed but if the spying allegations proved correct, "it's a huge scandal".

"It would be a big strain on the relations between the EU and the US," he added.

Luxembourg Foreign Minister Jean Asselborn said US spying was "out of control".

"The US would do better to monitor its intelligence services instead of its allies."

The top-secret PRISM programme collects and analyses information from Internet and phone users around the world, with access to data from Google, Yahoo! and other Internet firms.

US officials say the information gathered is vital in the fight against global terrorism.

The European bloc earlier demanded swift answers from Washington about the programme, warning of "grave adverse consequences" for the rights of EU citizens.

On Saturday Ecuadorean President Rafael Correa said the United States has asked his country to reject Snowden's asylum request.

Correa said he told US Vice President Joe Biden that Quito would consult with Washington before making a decision but that, ultimately, it was up to Ecuador whether to take in the fugitive who made bombshell revelations about covert US surveillance of phone records and Web traffic.

Quito held the United States in high regard and "did not seek out" being in this situation, Correa said he told Biden during Friday's call between the two men.

"Do not get the idea that we are anti-American, as some ill-spirited media outlets are doing," he said he told the vice president.

In his weekly address to the nation, Correa said he also told Biden that Ecuador could not process Snowden's asylum request because he was not physically in the country.

"When he comes to Ecuadoran soil, if in fact he ever does, and we have to process the request, the first people whose opinion we will seek is that of the United States," Correa said.

Snowden, currently holed up in the transit area of a Moscow airport after fleeing Hong Kong in the wake of his first disclosures to select media, asked for asylum last weekend.

Ecuador has already granted refuge to Julian Assange, founder of the anti-secrecy WikiLeaks website. Wanted for questioning in Sweden, the Australian has been hold up at Quito's embassy in London for the past year.