The National Security Agency denied German press reports Sunday that President Barack Obama was personally informed of U.S. spies tapping German Chancellor Angela Merkel's phones.

NSA chief General Keith Alexander "did not discuss with President Obama in 2010 an alleged foreign intelligence operation involving German Chancellor Merkel, nor has he ever discussed alleged operations involving Chancellor Merkel," spokeswoman Vanee' Vines said.

Germany has warned Israel to attend a periodic U.N. human rights review on Tuesday or face "severe diplomatic damage", Haaretz newspaper reported on Sunday.

Israel cut all ties with the Geneva-based U.N. Human Rights Council in March 2012, after it announced it would probe how Israeli settlements may be infringing on the rights of Palestinians.

U.S. President Barack Obama was personally informed of mobile phone tapping against German Chancellor Angela Merkel, which may have begun as early as 2002, German media reported Sunday as a damaging espionage scandal widened.

Bild am Sonntag newspaper quoted U.S. intelligence sources as saying that National Security Agency chief Keith Alexander had briefed Obama on the operation against Merkel in 2010.

German spy chiefs will travel to the United States next week to demand explanations following allegations that U.S. intelligence has been tapping Chancellor Angela Merkel's mobile phone.

"High-ranking government representatives will go rapidly to the United States in order to push forward discussions with the White House and the NSA on the allegations raised recently," said Georg Streiter, the chancellor's deputy spokesman, on Friday.

Germany and Brazil are working on a U.N. General Assembly resolution to highlight international anger at U.S. data snooping in other countries, diplomats said Friday.

The resolution would not mention the United States but would call for extending the International Covenant on Civil and Political Rights to Internet activities.

The alleged U.S. spying on German Chancellor Angela Merkel's mobile phone may have been run out of its Berlin embassy, less than a kilometer (mile) from the chancellery, media reported Friday.

The surveillance was allegedly conducted by a listening post of the Special Collection Service, run jointly by the National Security Agency (NSA) and the Central Intelligence Agency, said the Sueddeutsche Zeitung.

An advisor to U.S. President Barack Obama sought Thursday to assure the American people that the country's surveillance program is legitimate, but acknowledged it created "significant" challenges with allies.

"Though we collect the same sort of intelligence as all nations, our intelligence community has more restrictions and oversight than in any other country in history," Lisa Monaco, assistant to the president on homeland security and counterterrorism, wrote in an op-ed piece in the American daily USA Today.

France and Germany pushed Friday for Washington to agree rules for the spy game after damaging revelations the United States tapped German Chancellor Angela Merkel's mobile phone, the European Union said.

Leaders "took note of the intention of France and Germany to seek bilateral talks with the U.S.,” EU President Herman Van Rompuy told a press conference after a first day of summit talks wrapped up.

Brazil's President Dilma Rousseff on Thursday criticized alleged U.S. spying on German Chancellor Angela Merkel's phone calls, insisting on clear rules governing the Internet as a way to prevent it.

"Nobody, no democratic nation, will permit this violation of sovereignty and human and civil rights," said Rousseff, adding "there will be a growing reaction" from countries affected by the eavesdropping scandal.

The United States refused to say Thursday whether it had ever spied on Chancellor Angela Merkel, despite growing German anger over its evasive answers over the alleged tapping of her mobile phone.

The White House has been on tricky political ground since saying when the claims first surfaced on Wednesday that it is not, and will not monitor Merkel's communications.