* Snowden, in Moscow, eluding U.S. efforts to extradite him
* Russian officials defiant
* Ecuador says Snowden seeks asylum there
* Snowden expected to try to fly to Cuba next
* White House urges Russia to send Snowden to United States
Washington pressed Moscow on Monday to do all in its power to expel former U.S. spy agency contractor Edward Snowden before he gets the chance to take an expected flight to Cuba to evade prosecution in the United States for espionage.
Snowden, whose exposure of secret U.S. government surveillance raised questions about Washington's intrusion into private lives, was allowed to leave Hong Kong on Sunday after Washington had asked the Chinese territory to arrest him.
His decision to fly to Russia, which like China challenges U.S. dominance of global diplomacy, is another embarrassment to President Barack Obama who has tried to "reset" ties with Moscow and build a partnership with Beijing.
The White House said it expected the Russian government to send Snowden back to the United States and lodged "strong objections" to Hong Kong and China for letting him go.
"We expect the Russian government to look at all options available to expel Mr Snowden back to the U.S. to face justice for the crimes with which he is charged," said Caitlin Hayden, spokeswoman for the National Security Council.
The Kremlin and the Russian government did not immediately comment. But Russian officials were defiant, saying Moscow had no obligation to cooperate with Washington after it passed the so-called Magnitsky law, which can impose a visa ban and asset freeze on Russian officials accused of human rights violations.
"Ties are in a rather complicated phase and when ties are in such a phase, when one country undertakes hostile action against another, why should the United States expect restraint and understanding from Russia?" said Alexei Pushkov, the head of the foreign affairs committee in the lower house of parliament.
Pushkov does not speak for the Kremlin and is not a policy maker, but is an ally of President Vladimir Putin.
The lawmaker suggested Russia could consider granting asylum for Snowden if he required it, but it looked as if he would prefer to go to "other countries like Venezuela or Ecuador".
A spokesman for Putin said on Sunday the Russian leader was not aware of Snowden's location or plans. Russian leaders have not sought to draw attention to Snowden's arrival, and have not paraded him before cameras or trumpeted his arrival.
Ecuadorean Foreign Minister Ricardo Patino, on a trip to Vietnam, said Snowden had sought asylum in his country. He declined to say what the Ecuadorean government would do, but added the request would be analysed with a "lot of responsibility".
An aide said the minister would hold a news conference around 7.00 p.m. local time (1200 GMT) in Hanoi.
A source at Russian airline Aeroflot said Snowden was booked on a flight scheduled to depart for Havana on Monday at 2:05 p.m. (1005 GMT). Snowden is believed to be in the transit area of Moscow's Sheremetyevo airport.
Cuba said it had no information on Snowden's plans.
"HAND OF BEIJING"
A State Department official said Washington had told countries in the Western Hemisphere that Snowden "should not be allowed to proceed in any further international travel, other than is necessary to return him to the United States".
U.S. Senator Charles Schumer said Putin had probably known about and approved Snowden's flight to Russia. He predicted "serious consequences" for a U.S.-Russian relationship already strained over Syria and human rights.
"Putin always seems almost eager to stick a finger in the eye of the United States - whether it is Syria, Iran and now of course with Snowden," Schumer, a senior Senate Democrat, told CNN's "State of the Union". He also saw "the hand of Beijing" in Hong Kong's decision to let Snowden leave.
But taking the higher ground after being accused of hacking computers abroad, the Chinese Foreign Ministry expressed "grave concern" over Snowden's allegations that the United States had hacked computers in China.
It said it had taken up the issue with Washington.
Hong Kong's South China Morning Post newspaper reported Snowden's new details about U.S. surveillance activities, including accusations of hacking of Chinese mobile phone firms and the targeting of China's elite Tsinghua University, the alma mater of many of China's top leaders including President Xi Jinping.
Snowden was aided in his escape by WikiLeaks, the anti-secrecy organisation whose founder Julian Assange said he had helped to arrange documents from Ecuador.
Ecuador, like Cuba and Venezuela, is a member of the ALBA bloc, an alliance of leftist governments in Latin America that pride themselves on their "anti-imperialist" credentials. The Quito government has been sheltering Assange at its London embassy for the past year.
The New York Times quoted Assange as saying in an interview that his group had arranged for Snowden to travel on a "special refugee document" issued by Ecuador last Monday.
U.S. sources said Washington had revoked Snowden's passport. The New York Times said his passport was annulled a day before he left Hong Kong to try to thwart his escape.
WikiLeaks said Snowden was accompanied by diplomats and Sarah Harrison, a British legal researcher working for WikiLeaks.
U.S. FINDS HONG KONG DECISION "TROUBLING"
Snowden, who had worked at a U.S. National Security Agency facility in Hawaii, had been hiding in Hong Kong, a former British colony that returned to China in 1997, since leaking details about secret U.S. surveillance programmes to news media.
U.S. officials had been in contact with Hong Kong since June 10, and had expressed optimism about cooperation.
Snowden has been charged with theft of federal government property, unauthorised communication of national defence information and wilful communication of classified communications intelligence to an unauthorised person, with the latter two charges falling under the U.S. Espionage Act.
In a statement announcing Snowden's departure, Hong Kong authorities said they were seeking clarification from Washington about reports of U.S. spying on government computers in the territory.
A spokesman for the Hong Kong government said it had allowed the departure of Snowden as the U.S. request for his arrest did not comply with the law.
A U.S. Justice Department official said at no point in discussions through Friday did Hong Kong raise issues about the sufficiency of the U.S. arrest request. "In light of this, we find their decision to be particularly troubling," the official said.
Adding to the mystery, a Hong Kong lawyer representing Snowden said on Monday a middle man claiming to represent the Hong Kong government told Snowden he should leave.
Albert Ho, who is also a legislator, told reporters he was approached by Snowden several days ago, and that Snowden had sought reassurances from the Hong Kong government on whether he would be able to leave the city freely, if he chose to do so.
Ho said an individual claiming to represent the Hong Kong government had subsequently indicated to Snowden that he was free to leave the city and should do so. "This is a highly unusual action," said Ho.
Snowden's revelations have become a major problem for Obama, who has found his domestic and international policy agenda sidelined as he scrambled to deflect accusations that U.S. surveillance practices violate privacy protections and civil rights. The president has said the measures were necessary to thwart attacks on the United States.
The latest drama coincides with the court-martial of Bradley Manning, a U.S. soldier accused of providing reams of classified documents to WikiLeaks, which Assange began releasing on the Internet in 2010. The government says the leaks put national security and people's lives at risk.
Documents previously leaked by Snowden revealed that the NSA has access to vast amounts of Internet data such as emails, chat rooms and video from large companies, including Facebook and Google, under a government programme known as Prism.