Television journalists gave reports outside the Ecuador embassy in Moscow on Monday.
MOSCOW — Intrigue deepened on Monday over the whereabouts of Edward J. Snowden, the fugitive former National Security Agency contractor accused of espionage, when he did not leave Moscow on a planned flight to Havana, one day after the Chinese territory of Hong Kong frustrated his American pursuers by allowing him to leave on a Moscow-bound flight.
An exasperated Obama administration urged Russia to expel Mr. Snowden and return him to the United States, and said relations with China had been dealt a setback.
Mr. Snowden’s vacant seat on the Havana flight raised the possibility that the Russian government had detained him, either to consider the demands by the Obama administration to intercept him and return him to the United States or perhaps to question him for Russia’s own purposes.
The authorities in Hong Kong said Mr. Snowden boarded an Aeroflot flight to Moscow’s Sheremetyevo airport that arrived on Sunday afternoon. But he was never photographed in Hong Kong and has not been seen publicly or photographed since his reported arrival in Moscow. Arriving passengers on that flight, interviewed at the airport, said they could not confirm that he had been aboard.
The situation appeared to be increasingly infuriating for American officials, who have charged Mr. Snowden with illegally disclosing classified documents about American surveillance programs.
The Snowden pursuit dominated the questioning at the daily noon White House press briefing in Washington, where Jay Carney, the White House spokesman, reiterated the American view that the authorities in Hong Kong, which follows China’s directives, should have detained Mr. Snowden and had plenty of time to do so. “We see this as a setback, in terms of efforts to build mutual trust,” Mr. Carney told reporters.
He also said “it is our understanding that Mr. Snowden remains in Russia” and that “we have asked the Russians to look at the options available to them to expel Mr. Snowden back to the United States.”
Earlier Monday on a visit to New Delhi, Secretary of State John Kerry also emphasized that Russia should send Mr. Snowden to the United States. "I would urge them to live by the standards of the law,” Mr. Kerry said.
Security was extremely tight at the gate at Sheremetyevo airport on Monday as agents called passengers to board the Havana-bound Aeroflot aircraft. Police officers stood around the plane on the tarmac, and the entrance to the gate inside the terminal was cordoned off with about 25 feet of blue ribbon.
Mr. Snowden was said to have reserved a ticket on the flight, Aeroflot Flight 150, in coach seat 17A. But just before the plane pulled away, Nikolay Sokolov, an Aeroflot employee at the gate, said that Mr. Snowden was not on board. “He is not there,” Mr. Sokolov said. “I was waiting myself.” A police officer asked a member of the ground crew if everyone had arrived. The reply was: “Minus five.”
WikiLeaks, the antisecrecy group, has said that Mr. Snowden approached it for support and legal advice, and that it has advised him on seeking asylum. It also has helped him get a temporary refugee travel document from Ecuador’s government to use after his American passport was revoked on Saturday.
In a telephone conference call with reporters on Monday morning, Julian Assange, the WikiLeaks founder, said Mr. Snowden was “healthy and safe” but declined to specify his whereabouts.
Speaking from his own refuge in the Ecuadorean Embassy in London, Mr. Assange said that reports that Mr. Snowden had been questioned by Russian intelligence were false. Asked about reports that Mr. Snowden had been questioned by the Chinese authorities, Mr. Assange said: “As far as I’m aware, that is false.”
Earlier on Monday, the group posted a message on Twitter criticizing the United States.
“US bullying Russia for Snowden’s rendition is counterproductive,” it said. “No self-respecting state would accept such unlawful demands.” The use of “rendition” was an explicit reference to the way the United States has handled terrorism suspects.
David M. Herszenhorn and Ellen Barry reported from Moscow, and Peter Baker from Washington. Reporting was contributed by Andrew Roth from Moscow; Scott Shane, Steven Lee Myers and Charlie Savage from Washington; Keith Bradsher from Hong Kong; Michael R. Gordon from New Delhi; and Rick Gladstone from New York.
