The whereabouts of Edward Snowden, the former National Security Agency contractor who leaked details of secret US surveillance programs, are unknown after he failed to board a flight from Moscow to Havana on Monday.
White House spokesman Jay Carney said Monday the administration expects Russian authorities to expel Snowden to face charges in the US.
"It's our understanding that Mr. Snowden remains in Russia," Carney said. "We have a strong cooperative relationship with the Russians on law enforcement matters."
US President Barack Obama said on Monday that Washington was following “all appropriate legal channels” and working with “various other countries” to try to bring Snowden back home.
Snowden, who arrived in the Russian capital from Hong Kong Sunday morning, was booked onto a Cuba-bound flight departing at 2:05 PM the next day, a spokesman for Russia's Aeroflot airline told the Associated Press.
When the flight took off from Moscow's Sheremetyevo airport, however, Snowden's seat was empty — as several journalists onboard testified.
An Aeroflot employee confirmed to Reuters that Snowden had not boarded the plane.
More from GlobalPost: Where in the world is NSA leaker Edward Snowden?
Snowden is expected to attempt to reach Ecuador, where he has requested asylum.
The United States, which is seeking to try Snowden on charges of leaking classified information, has revoked his passport and urged Western countries to comply with its demands to return him.
The White House said Monday the administration is "not buying" claims by the Hong Kong authorities that it let Snowden go to Russia because of a technical decision.
Before Snowden left Hong Kong, he celebrated his 30th birthday over some pizza and fried chicken, one of his lawyers told The Wall Street Journal, citing another legal source as saying the Russia idea was "very sudden."
Snowden's lawyer and Hong Kong legislator, Albert Ho, and an unidentified source in Beijing, both told Reuters that China had orchestrated Snowden's flight to Moscow to avoid an extradition battle with Washington.
"One-hundred percent there was communication between Hong Kong and the (Chinese) central government regarding how to handle Snowden," the source said.
The White House spokesman reiterated on Monday that Snowden's release "unquestionably" damages US-China relations.
Secretary of State John Kerry warned that there would be "consequences" if Russia allowed him to continue his journey.
“Overall, we have no information about him,” Dmitri Peskov, the spokesman for President Vladimir V. Putin, said on Monday, keeping in line with other high-ranking Russian officials who denied to have any knowledge of Snowden's plans or location.
But it appears that WikiLeak's Julian Assange knows a few things about the NSA leaker.
If Ecuador decides to grant him asylum, the government could issue him with the travel documents necessary to make his way there, a Russian official told Interfax news agency.
The Ecuadorean government is studying Snowden's request, Foreign Minister Ricardo Patino said Monday, stressing that "We always act by principle, not in our own interest."
Snowden's case "has to do with freedom of expression and the security of citizens around the world," Patino told reporters.