* Russia defies calls to send Snowden to United States
* Snowden not seen on Moscow-to-Havana flight
* Ecuador says Snowden seeks asylum there (Adds no sign of Snowden aboard Cuba flight, China's role)
By Lidia Kelly and James Pomfret
MOSCOW/HONG KONG, June 24 (Reuters) - Russia defied White House pressure on Monday to expel former U.S. spy agency contractor Edward Snowden to the United States before he flees Moscow on the next stop of his globe-crossing escape from U.S. prosecution.
Snowden, whose exposure of secret U.S. government surveillance raised questions about intrusions into private lives, was allowed to leave Hong Kong on Sunday after Washington asked the Chinese territory to arrest him on espionage charges.
The 29-year-old flew to Moscow as a transit stop before heading elsewhere, several sources said. But reports he would fly to Cuba were put in doubt when witnesses could not see him on the plane, despite heightened security before take-off.
Ecuador, which has sheltered the founder of the WikiLeaks anti-secrecy organisation, Julian Assange, said it was considering Snowden's request for asylum. There is no direct flight to Quito from Moscow.
"He didn't take the flight (to Havana)," a source at Russia's national airline Aeroflot told Reuters.
As speculation mounted about where he would go next - Ecuador, Venezuela or Havana at a later date to escape the crowd of journalists on board Monday's flight - Washington was stung by Russian defiance.
Snowden's flight to Russia, which like China challenges U.S. dominance of global diplomacy, is an 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.
But the Russian government ignored the appeal and President Vladimir Putin's press secretary denied any knowledge of Snowden's movements.
Asked if Snowden had spoken to the Russian authorities, Peskov said: "Overall, we have no information about him."
He declined comment on the expulsion request but other Russian officials said Moscow had no obligation to cooperate with Washington, after it passed legislation to impose visa bans and asset freezes on Russians accused of violating human rights.
"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.
Putin has missed few chances to champion public figures who challenge Western governments and to portray Washington as an overzealous global policeman. But Russian leaders have not paraded Snowden before the cameras or trumpeted his arrival.
Since leaving Hong Kong, where he feared arrest and extradition, Snowden has been searching for a country that can guarantee his security.
Ecuadorean Foreign Minister Ricardo Patino, on a trip to Vietnam, said Quito would analyse his asylum request with a "lot of responsibility". He was expected to hold a news conference around 7 p.m. (1200 GMT) in Hanoi.
A source at Aeroflot said on Sunday Snowden was booked on the flight due to depart for Havana on Monday at 2:05 p.m. (1005 GMT). But a correspondent aboard could not see him and the seat he was supposed to occupy, 17a, was taken by another passenger.
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".
Despite the Kremlin denials, U.S. Senator Charles Schumer said Putin had probably known about and approved Snowden's flight to Russia.
"Putin always seems almost eager to stick a finger in the eye of the United States," 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.
Some Russians have praised Snowden's revelations. Others fear a new chill in relations with the United States.
"We are a pretty stubborn country and so is the United States. Both are mighty countries, so I would say this has a good potential to turn into a big fuss in bilateral relations," said Ina Sosna, manager of a Moscow cleaning company.
"I guess it would be best if they just let him move on from Russia to avoid any more controversy over him being here."
Snowden was assisted in his escape by WikiLeaks, whose founder 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. WikiLeaks said diplomats and Sarah Harrison, a British legal researcher working for the anti-secrecy group, accompanied him.
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.
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. (Additional reporting by Gabriela Baczynska and Alexei Anishchuk in Moscow, Martin Petty in Hanoi, Sui-Lee Weein in Beijing,; Andrew Cawthorne, Mario Naranjo and Daniel Wallis in Caracas, Alexandra Valencia in Quito and Mark Felsenthal, Paul Eckert and Mark Hosenball in Washington; Writing by Timothy Heritage and Elizabeth Piper, Editing by)