US will not seek to intercept Edward Snowden

US jets will not be sent to intercept Edward Snowden, the wanted intelligence whistle-blower, if he flies out of Russia to seek a safe passage to another country, Barack Obama said on Thursday.

"I'm not going to be scrambling jets to get a 29-year-old hacker," said the US president during a visit to Senegal. His comment came as mystery persisted over Snowden's whereabouts after he failed to show up for a third time for a flight to Havana, Cuba, at Moscow's Sheremetyevo airport.

Vladimir Putin, the Russian president, said on Tuesday that the former CIA and National Security Agency contractor was in the airport's transit zone after flying in from Hong Kong on Sunday. He was expected to fly on to Cuba on a flight path that can skirt US airspace.

Snowden, who turned 30 last week, is wanted on espionage charges in the US after disclosing details of alleged surveillance of Americans' telephone calls and emails. He is seeking a safe haven to avoid extradition and has reportedly applied for asylum in Ecuador.

Reporters have combed Sheremetyevo's departures and transit zone all week looking for the American without seeing him, leading to speculation that Russian officials have helped him stay in a closed area, where they may be questioning him.

A Russian immigration source told The Daily Telegraph that passengers could stay in the transit zone "as long as they want" but would not be able to enter Russia proper without a visa.

"There has been no request from the foreign ministry or President Putin to issue a visa [to Snowden], and he has not asked for one," he added. He could not confirm if the American was at the airport. There was no sign of Snowden as an Aeroflot plane left Sheremetyevo's Gate 25 for Havana yesterday.

Airline staff earlier said he was not booked on the flight, and neither was Sarah Harrison, the WikiLeaks researcher accompanying him. Journalists who flew said they could not find the whistle-blower on board before take-off.

Obama said he had not spoken to Putin or China's president, Xi Jinping, about Snowden. "I'm not going to have one case of a suspect who we're trying to extradite suddenly being elevated to the point where I've got to start doing wheeling and dealing and trading on a whole host of other issues simply to get a guy extradited, so that he can face the justice system in the United States," he said.