Merkel and Obama bury hatchet on US spying

Back then, Merkel was outraged and said this was a "breach of trust" among friends.

But the criticism has since faded. According to senior German officials, Merkel has accepted that there will be no "no-spying agreement" with the US, because the American side is unwilling to sign up to such a deal.

"We are not expecting any substantial progress after this visit in translating the goals the Chancellor is seeking," the official said.

Rather than seeking a bilateral deal, Germany is now eyeing an international effort at EU and UN level. "This is an tough nut to crack over the next years," another German official said.

On the other hand, efforts by the German Greens to bring NSA whistleblower Edward Snowden to Germany for hearings are being put on ice by Merkel's government.

In a letter to members of a parliamentary committee obtained by Sueddeutsche Zeitung, government officials say a personal invitation for the US whistleblower would "run counter to the political interests of Germany", and "put a grave and permanent strain" on US-German relations.

The letter was sent just a few days before Merkel's visit to Washington, which to the Greens' is an indication that the only goal is for "Obama not to be upset" and that the Chancellor shows "cowardice towards friends."

But Merkel's concessions are not unilateral.

In a report released just hours before her visit, reviewing intelligence activities including the bugging of Merkel's phone, the White House is pledging to extend data privacy protections to non-US citizens.

The report on "Big Data and Privacy" makes six recommendations, most of which rely on Congress to pass additional legislation or review existing guidelines.

But in conference call with reporters the author of the report, John Podesta, said that work to apply the 1974 Privacy Act to non-US persons would begin immediately and could be completed within six to 12 months, British daily The Guardian reports.

Merkel's visit to Washington coincides with the visit of European Commission chief Jose Manuel Barroso, who has no meetings with Obama, but will meet the CEO of Apple, Tim Cook.