The White House on Thursday expressed "extreme disappointment" at Russia's grant of temporary asylum for fugitive American intelligence leaker Edward Snowden, saying Washington was evaluating a scheduled presidential summit in September.

"We are extremely disappointed that the Russian government would take this step, despite our very clear and lawful requests in public and in private to have Mr. Snowden expelled to the United States to face the charges against him," spokesman Jay Carney said at a daily press briefing.

"This move by the Russian government undermines a longstanding record of law enforcement cooperation, cooperation that has recently been on the upswing since the Boston Marathon bombings" on April 15, he added.

Snowden, who had been marooned at the transit area of Moscow's Sheremetyevo airport since his arrival there on June 23, left earlier Thursday for a safe place in Russia after being granted temporary asylum for one year by the Russian Federal Migrant Service.

The 30-year-old former American spy agency contractor was revoked of his passport and charged with espionage, theft and unauthorized communication of national defense and intelligence information, following his disclosure in early June of massive secret phone and Internet surveillance programs of the U.S. National Security Agency.

"Mr. Snowden is not a whistleblower," Carney remarked. "He is accused of leaking classified information and has been charged with three felony counts, and he should be returned to the United States as soon as possible, where he will be accorded full due process and protections."

U.S. Attorney General Eric Holder sent a letter days ago to Russian authorities, promising the United States will not seek death penalty for Snowden, and he will not be tortured either.

Moscow's refusal to budge on Washington's demand for the return of Snowden has strained bilateral relations, as the White House has refused to talk about a planned summit between President Barack Obama and his Russian counterpart Vladimir Putin when he travels to Russia in September for the Group of 20 meeting in St. Petersburg.

"I don't have a scheduling announcement for you today, but obviously this is not a positive development," Carney said. "And we have a wide range of interests with the Russians, and we are evaluating the utility of a summit."

But he said U.S.-Russian relationship is based on "realism," and Obama's reset in bilateral ties during his first term has produced "positive benefits" for the United States, including Russia's cooperation on Afghanistan and Iran and the signing of a New Strategic Arms Reduction Treaty.