The United States was in touch through diplomatic and law enforcement channels with countries that Snowden could travel through or to, reminding them that Snowden is wanted on criminal charges and reiterating Washington's position that Snowden should only be permitted to travel back to the U.S., a State Department official said. Snowden's U.S. passport has been revoked.
U.S. officials spoke on condition of anonymity because they were not authorized to publicly discuss the case.
An unidentified Aeroflot airline official was cited by Russia's state ITAR-Tass news agency and Interfax as saying Snowden was on the plane that landed Sunday afternoon in Moscow. The Russian report said Snowden intended to fly to Cuba on Monday and then on to Caracas, Venezuela.
The White House was hoping to stop Snowden before he left Moscow.
Caitlin Hayden, a spokeswoman for the National Security Council, said, "Given our intensified cooperation after the Boston marathon bombings and our history of working with Russia on law enforcement matters — including returning numerous high-level criminals back to Russia at the request of the Russian government — 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."
Still, the United States is likely to have problems interrupting Snowden's passage. The United States does not have an extradition treaty with Russia, but does with Cuba, Venezuela and Ecuador. Even with an extradition agreement though, any country could give Snowden a political exemption.
The likelihood that any of these countries would stop Snowden from traveling on to Ecuador seemed remote. While diplomatic tensions have thawed in recent years, Cuba and the United States are hardly allies after a half-century of distrust. Another country that could see Snowden pass through, Venezuela, could prove difficult, as well. Former President Hugo Chavez was a sworn enemy of the United States and his successor, Nicolas Maduro, earlier this year called President Barack Obama "grand chief of devils." The two countries do not exchange ambassadors.