European powers have pressed the US and Denmark over reports the two worked together to spy on top European politicians, including German Chancellor Angela Merkel.

Danish broadcaster DR said Denmark's Defence Intelligence Service (FE) collaborated with the US National Security Agency (NSA) to gather information from 2012 to 2014.

Mrs Merkel is among those demanding answers.

Both FE and the NSA are yet to comment.

Denmark's Defence Minister, Trine Bramsen, did not confirm or deny the report but told AFP news agency that "systemic eavesdropping of close allies is unacceptable". She was not in charge of the ministry during the alleged spying.

"This is not acceptable between allies, and even less between allies and European partners," said French President Emmanuel Macron, after speaking with Mrs Merkel.

Mrs Merkel said she agreed with Mr Macron's comments, but that she was also reassured by the Danish defence minister's condemnation.

Intelligence was allegedly collected on other officials from Germany, France, Sweden and Norway. Those nations have also called for explanations.

Norwegian Prime Minister Erna Solberg told public broadcaster NRK: "It's unacceptable if countries which have close allied co-operation feel the need to spy on one another."

What are the allegations?

The NSA is said to have accessed text messages and the phone conversations of a number of prominent individuals by tapping into Danish internet cables in co-operation with the FE.

The alleged set-up, said in the report to have been codenamed "Operation Dunhammer", allowed the NSA to obtain data using the telephone numbers of politicians as search parameters, according to DR.

DR interviewed nine sources, all of whom are said to have had access to classified information held by the FE.

Along with Mrs Merkel, then-German Foreign Minister Frank-Walter Steinmeier and the opposition leader at the time, Peer Steinbrück, are also said to have been targeted.

Similar allegations emerged in 2013.

Then, secrets leaked by US whistleblower Edward Snowden alleged tapping of the German chancellor's phone by the NSA.

When those allegations were made, the White House gave no outright denial but said Mrs Merkel's phone was not being bugged at the time and would not be in future.

Following the new report, Mr Snowden accused US President Joe Biden of being "deeply involved in this scandal the first time around". Mr Biden was US vice-president at the time the reported surveillance took place.

"There should be an explicit requirement for full public disclosure not only from Denmark, but their senior partner as well," he tweeted.

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