The United States may boycott a planned summit with president Vladimir Putin next month in protest at Russia's decision to grant whistleblower Edward Snowden asylum.

The White House said it was "extremely disappointed" at the decision to give Snowden sanctuary in Russia, adding that a high-profile meeting between Barack Obama and Putin, scheduled for next month, was now being reconsidered.

"It is not just a legal matter," said Obama's spokesman, Jay Carney. "There is the matter with our relations with Russia."

"We are extremely disappointed that the Russian government would take this step despite our very clear and lawful requests in public and private that Mr Snowden be expelled and returned to the United States," Carney said. "This move by the Russian government undermines a long-standing record of law enforcement co-operation."

The decision to grant Snowden asylum threatens to cause a diplomatic rift between the US and Russia, undoing recent attempts to heal relations.

Obama was scheduled to travel to Russia in September for at meeting of G20 leaders in St Petersburg. He also planned to meet with Putin for a bilateral summit during the trip in what would have been a sign of improving relations between the two powers.

However, that meeting is now under review. "Obviously this is not a positive development," Carney said. "We have a wide range of interests with the Russians. We are evaluating the utility of the summit."

At previous White House briefings, Carney had consistently said that, despite the controversy over Snowden, Obama still "intended" to meet the Russian president.

Snowden slipped out of Sheremetyevo airport on Thursday afternoon. His lawyer, Anatoly Kucherena, said Russia's federal migration service had granted him temporary asylum for one year.

Carney said that the US had not been given "any advance notice" of the decision by Russia. He also hinted at concerns that Russia would be able to access state secrets held by the former NSA contractor.

"Let's be clear, Mr Snowden has been, since he left the United States, in possession of classified material in China and in Russia. Simply the possession of that kind of highly sensitive, classified information outside of secure areas is both a huge risk and a violation. He has been in Russia now for many weeks."

Carney repeated the position of the Obama administration that Snowden is not a whistleblower. "He is accused of leaking classified information and has been charged with three felony accounts."

However, reporters pressed the spokesman on the Obama administration's continued insistence that Snowden is not a whistleblower.

In the wake of the scandal sparked by Snowden's leaks, some members of Congress have expressed concerns over the breadth of US surveillance capabilities.

Less than 30 minutes after the White House briefing, which which was almost completely dominated by Snowden and the fallout over his leaks, Obama was scheduled to meet with congressmen to discuss NSA surveillance tactics.

Carney said that some of those at the meeting were critics of the administration and said Obama wanted to to hear their "concerns and issues".

Asked by a journalist whether Snowden had actually done the US "a favour", Carney said unauthorised leaking had done "enormous damage" to US interests. He said: "When you take an oath to protect the secrets of the US, you are bound to protect them, and there are consequences if you don't."