The U.S. government said Sunday that it has initiated contacts through "diplomatic and political channels" with Latin American countries through which Edward Snowden may travel after Washington accused the former CIA employee of spying and prepared an extradition request for him.

The U.S. government went on to advise Latin American governments that Snowden - a former National Security Administration contractor - is wanted on serious criminal charges and should not be permitted to do any more traveling around the world after already traveling to Hong Kong and Russia - or to any country that could serve as his final asylum destination, a top official in the Barack Obama administration told Efe, requesting anonymity.

The official did not mention any countries by name, but WikiLeaks, which on Sunday helped Snowden abandon Hong Kong and travel to Russia, said on its Web page that he will travel on to Ecuador by a safe route after requesting political asylum there.

When asked by Efe about the possibility that Snowden will travel to Ecuador and receive political asylum there, the U.S. official said that he/she would not discuss hypothetical situations.

The United States and Ecuador have had an extradition treaty in place since 1872 and supplemented it in 1939.

Last year, Quito granted WikiLeaks founder Julian Assange asylum, but he is still in the Ecuadorian Embassy in London awaiting a safe conduct guarantee from Great Britain.

Ecuadorian Foreign Minister Ricardo Patiño said Sunday on his Twitter account that Snowden had asked Quito for asylum but he provided no further details, saying only: "The Ecuadorian government received an asylum request from Edward #Snowden."

Meanwhile, a flight from Hong Kong landed in Moscow at 5:05 p.m. local time (1305 GMT) and a source with the Russian news agency Interfax said that "Passenger Edward Snowdon not only registered for the flight but it is also absolutely certain that is on board the aircraft. He put his name on the embarkation list" in Hong Kong.

The source added that speculation was that Snowden will spend the night in the Venezuelan Embassy in the Russian capital, although the situation was unclear and apparently it was Ecuadorian officials who contacted the U.S. citizen in Moscow after he landed.

The Interfax source also said that Snowden could be welcomed by Venezuelan (or other) embassy personnel right at the aircraft stairway, immediately enter a diplomatic vehicle and be taken to a foreign embassy, not formally entering Russian territory and thus not being subject to arrest by Russian authorities.

However, local news agencies in Moscow reported that Snowden has not left the airport because he does not have a Russian visa.

U.S. federal prosecutors charged Snowden, who leaked classified documents about government surveillance programs to media outlets, with theft of government property and violations of the 1917 Espionage Act, the Washington Post reported on the weekend.

The criminal complaint was filed last week under seal in federal court in Virginia, U.S. authorities told the daily. Each of the charges - unsealed on Friday - carries a maximum sentence of 10 years in prison.

Snowden, 30, fled to Hong Kong in early June after leaking a haul of documents about two top-secret NSA surveillance programs to London newspaper The Guardian and The Washington Post.

His leaks brought to light programs to store data on virtually all phone calls in the United States and collect e-mails of foreigners and have sparked debate about the proper scope of government surveillance and to what extent the NSA should be allowed to infringe upon people's privacy.

According to the complaint, Snowden has been charged with "theft of government property, unauthorized communication of national defense information, and willful communication of classified communications intelligence information to an unauthorized person."

State Department spokesperson Jen Psaki said on Sunday that the U.S. government revokes the passports of citizens wanted for serious crimes although that does not affect their citizenship.

Several experts assured Sunday television analysis programs in the United States that an extradition treaty does not necessarily guarantee that a person will be returned to the United States, and in any case that process can take many months. EFE