Russia says it has had no involvement in the travel plans of fugitive US intelligence leaker Edward Snowden.
The exact whereabouts of Snowden, who flew to Moscow from Hong Kong on Sunday, are unclear.
Foreign Minister Sergei Lavrov insisted he had not crossed the Russian border
He criticized what he termed US attempts to blame Russia for his disappearance, saying they were "groundless and unacceptable".
Correspondents say Lavrov's comments suggest that Snowden remained air-side after landing at Moscow's Sheremetyevo airport, and so has technically never entered Russian territory.
"We are in no way involved with either Snowden, his relations with US justice, nor to his movements around the world," Lavrov said.
"He chose his itinerary on his own. We learnt about it... from the media. He has not crossed the Russian border.
"We consider the attempts to accuse the Russian side of violating US laws, and practically of involvement in a plot, to be absolutely groundless and unacceptable."
The 30-year-old IT expert is wanted by the US for revealing to the media details of a secret government surveillance programme, which he obtained while working as a contractor for the National Security Agency (NSA).
He is charged with theft of government property, unauthorized communication of national defense information and willful communication of classified communications intelligence.
Snowden has applied for asylum in Ecuador. The US has revoked his passport.
Reuters news agency quotes a Moscow airport source as saying that Snowden arrived in Moscow from
Hong Kong on Sunday afternoon and was due to depart for the Cuban capital, Havana, the following day, but did not use the ticket.
The source said he was traveling with Sarah Harrison, a British legal researcher working for the anti-secrecy group Wiki leaks.
Meanwhile, China has also described US accusations that it facilitated the departure of fugitive Edward Snowden from Hong Kong as "groundless and unacceptable".
A foreign ministry spokeswoman said the Hong Kong government had handled the former US intelligence officer's case in accordance with the law.
The White House had criticized what it termed "a deliberate choice to release a fugitive despite a valid arrest warrant".
The Chinese government has expressed deep concern about Snowden's allegations that the US had hacked into networks in China.
Tuesday saw the official newspaper of the Chinese Communist Party praise Snowden for "tearing off Washington's sanctimonious mask".
In a strongly worded front-page commentary, the overseas edition of the People's Daily said: "Not only did the US authorities not give us an explanation and apology, it instead expressed dissatisfaction at the Hong Kong Special Administrative Region for handling things in accordance with law.
"In a sense, the United States has gone from a 'model of human rights' to 'an eavesdropper on personal privacy', the 'manipulator' of the centralized power over the international internet, and the mad 'invader' of other countries' networks."
Speaking during a visit to India, US Secretary of State John Kerry said it would be "deeply troubling" if it became clear that China had "willfully" allowed him to fly out of Hong Kong.
"There would be without any question some effect and impact on the relationship and consequences," he said.
He also called on Russia to "live by the standards of the law because that's in the interests of everybody".
Snowden was in hiding in Hong Kong when his leaks were first published.