Barack Obama has called for the end of his government's control over phone data from hundreds of millions of Americans, promising that US intelligence would no longer be listening in on the telephone conversations of world leaders of friendly nations.
The existence of the US intelligence programme that bugged the phones of leaders including Germany's chancellor Angela Merkel and Brazilian president Dilma Rousseff significantly cooled relations with some of Washington's key partners abroad.
Ms Merkel made her displeasure broadly known and Ms Rousseff blasted the United States at the United Nations and cancelled a planned US trip that was supposed to culminate in a coveted state dinner at the White House on October 23.
"The leaders of our close friends and allies deserve to know that if I want to learn what they think about an issue, I will pick up the phone and call them, rather than turning to surveillance," President Obama said in a major speech yesterday.
But in a telephone briefing with reporters before the president's speech, a senior administration official said he could not specify who those leaders were.
"We frankly can't be in the business of going individual by individual to determine every foreign leader that we may or may not be collecting intelligence on," the official said.
"So this is not just the case where Angela Merkel is not being subject to surveillance. ... We've determined that we will not pursue this type of surveillance on the order of dozens of leaders."
The revelations of the vast collection of phone and internet data both at home and abroad laid a broad stain on the United States which prides itself as a protector of human rights and policies that guarantee individual privacy.
In addition to promising greater privacy protections at home and among friendly leaders, Mr Obama called for extending some privacy protections to foreign citizens whose communications are scooped up by the US.
"The bottom line is that people around the world - regardless of their nationality - should know that the United States is not spying on ordinary people who don't threaten our national security, and that we take their privacy concerns into account. This applies to foreign leaders as well," he said.
The moves are more sweeping than many US officials had been anticipating. In Mr Obama's highly-anticipated speech, after months of revelations about US spying by former National Security Agency analyst Edward Snowden, he said intelligence officials did not intentionally abuse the programme to invade privacy.
Some privacy advocates have pressed Mr Obama to grant fugitive Mr Snowden amnesty or a plea deal if he returns to the US from Russia, where he has been given temporary asylum, but the White House has so far dismissed those ideas.
But Mr Obama also said he believed critics of the programme were right to argue that without proper safeguards, the collection could be used to obtain more information about Americans' private lives and open the door to more intrusive programmes.
He said the US had a "special obligation" to re-examine its intelligence capabilities because of the potential for trampling on civil liberties.
As part of his speech, Mr Obama said the government should end its practice of holding phone records of Americans but did not say whether that duty should be given to the telephone companies or a third party. He also said the government should be required to obtain court approval to study the records.
He called the leaks from Mr Snowden "sensational" revelations of classified spying programmes that could affect US operations for years to come.
Although the president has said he welcomed the review of the nation's sweeping surveillance programmes, it is all but certain the study would not have happened without Mr Snowden's actions.
Mr Obama warned, however, that "we cannot unilaterally disarm our intelligence agencies", adding: "We know that the intelligence services of other countries - including some who feign surprise over the Snowden disclosures - are constantly probing our government and private sector networks."
But he said the US must be held to a higher standard. "No one expects China to have an open debate about their surveillance programmes, or Russia to take the privacy concerns of citizens into account," he said.
Overseas reaction was welcome but wary.
The European Commission said it welcomed Mr Obama's plans but said: "Trust in EU-US data flows has been affected by revelations on these intelligence programmes and needs to be rebuilt. In recognising the need for action, President Obama has taken important steps towards rebuilding that trust."
Senior German politician Phillipp Missfelder, a member of Ms Merkel's party, said: "Obama's speech is an important contribution toward restoring the trust we've lost in our close friend and ally in the past months."
In Brazil, MP Vanessa Grazziotin, whose Senate panel is investigating US espionage, said: "Besides the words of the American president, the entire world wants concrete actions of respect for the sovereignty of nations."