Russia’s decision, which infuriated American officials, ended five weeks of legal limbo for Mr. Snowden, the former intelligence analyst wanted by the United States for leaking details of the National Security Agency’s surveillance programs, and opened a new phase of his legal and political odyssey.

Even as his leaks continued with new disclosures from the computer files he downloaded, Mr. Snowden now has legal permission to live — and conceivably even work — anywhere here for as long as a year, safely out of the reach of American prosecutors. Though some supporters expect him to seek permanent sanctuary elsewhere, possibly in Latin America, Mr. Snowden now has an international platform to continue defending his actions as a whistle-blower exposing wrongdoing by the American government.

In a statement issued by WikiLeaks, the antisecrecy organization that has been assisting him since he made his disclosures in June, Mr. Snowden thanked Russia for giving him permission to enter the country “in accordance with its laws and international obligations.” He accused the Obama administration of disregarding domestic and international law since his disclosures, but added that “in the end, the law is winning.”nytimes.com

White House officials indicated that Mr. Obama was leaning against his plan to meet President Vladimir V. Putin of Russia in Moscow next month after the summit meeting of the Group of 20 nations in St. Petersburg, though officials stopped short of canceling the meeting outright. While American and Russian officials acknowledge the need to work together on issues of global importance, like the reduction of nuclear weapons and the war in Syria, Mr. Snowden’s case now casts a shadow over relations in the way little has since the days of cold war defections.

“We are extremely disappointed that the Russian Federation would take this step,” the White House press secretary, Jay Carney, said in Washington. He pointedly added that the administration was evaluating “the utility of having a summit.”

Mr. Putin, who spent the day at his official residence on the outskirts of Moscow, has appeared increasingly impervious to entreaties from the United States — even those directly from Mr. Obama, who called him last month to discuss Mr. Snowden’s case.

Mr. Putin, who met with the president of Tajikistan, in part to discuss the impact of the American withdrawal from Afghanistan next year, made no public comments about Mr. Snowden on Thursday. The Kremlin’s spokesman, Dmitri S. Peskov, said the decision had been made by immigration officials and not by Mr. Putin himself, though it is widely assumed here that any decision with such potentially severe diplomatic consequences would require approval from the Kremlin.

“It has nothing to do with the president or his administration,” Mr. Peskov said in a telephone interview.

The Kremlin seemed to dare the White House to cancel the summit meeting. Mr. Peskov said that Russia continued to prepare to hold the meetings in Moscow and would until notified otherwise. He said that Russia believed in the importance of the relationship for ensuring regional and global security, but he shifted the onus to the Obama administration. “You cannot dance tango alone,” he said.

By late Thursday night, Mr. Snowden’s whereabouts remained unclear. He left the international transit zone at Sheremetyevo airport unexpectedly at 3:30 p.m. after his lawyer, Anatoly G. Kucherena, spent the day with officials from the Federal Migration Service. Mr. Kucherena delivered him a passport-like document issued Wednesday and valid until July 31, 2014, granting him status as a “temporary refugee” in Russia.

Mr. Kucherena, in an interview, said he would not disclose Mr. Snowden’s whereabouts, though he expected that he could make a public appearance soon. “I cannot give out details,” he said in an interview.

WikiLeaks said that Mr. Snowden was accompanied by one of its representatives, Sarah Harrison, who appears to have remained with him since his flight began in Hong Kong in June. Mr. Kucherena said in television interviews that while he would continue to act as counsel, he was not involved in arrangements for Mr. Snowden’s housing in Russia.

Mr. Snowden, 30, could still decide to seek permanent asylum in another country. According to Mr. Kucherena, he has not officially applied for permanent political asylum in Russia and could simply remain until he is able to fly elsewhere, though the logistics of that have been complicated by intense pressure from the Obama administration on countries to block his transit.

After Mr. Snowden’s departure from the Moscow airport on Thursday there was frenzied news media speculation, including one specious report that he was headed to a notorious expatriate bar known as the Hungry Duck that had in fact closed.

Mr. Snowden’s official arrival in Russia was broadly cheered by many here who have defended his decision to leak the secrets of American surveillance. Ivan Melnikov, a senior Communist Party member of Parliament and a candidate for mayor of Moscow in next month’s election, called him a hero. “Frankly speaking,” Mr. Melnikov said, according to the Interfax news agency, he is “like a balm to the hearts of all Russian patriots.”

Pavel Durov, the founder of the most prominent Russian online social network, VKontakte, even invited Mr. Snowden to join his company and help create new security measures. “Snowden might be interested in working to protect the personal data of millions of our users,” he wrote.

Lyudmila M. Alekseyeva, the head of the Moscow Helsinki Group and a stalwart of the human rights movement here since the Soviet era, welcomed the government’s decision. “I am satisfied that this happened,” Ms. Alekseyeva, who met Secretary of State John Kerry in Moscow in May, told Interfax.

Although Mr. Putin has sought to avoid a personal confrontation with Mr. Obama over Mr. Snowden — calling his limbo in the airport “an unwanted Christmas present” — officials across the political spectrum have delighted in criticizing what they perceive as American arrogance and hypocrisy. Robert Shlegel, a member of Parliament in the pro-Kremlin majority party, United Russia, noted that the disclosures exposed surveillance efforts against American allies in Europe as well.

“Will Obama cancel meetings with their leaders, too?” he said.

Andrew Roth and Nikolay Khalip contributed reporting from Moscow, and Mark Landler from Washington.