At least three people, including two British citizens, were killed in Russia's Far North on Sunday when a helicopter crashed into them while they were standing on the ground, officials said.

A distress signal had already been received from the Eurocopter-120 before it made the hard landing on the north of the Kola peninsula in the Murmansk region.

Hundreds of supporters greeted the charismatic Russian opposition leader Alexei Navalny as he returned to Moscow on Saturday after his surprise release from jail and vowed to push forward with his campaign to become mayor of the Russian capital.

Navalny was sentenced to five years in prison on an embezzlement conviction on Thursday in the city of Kirov, but prosecutors unexpectedly asked for his release the next morning. They said that keeping him behind bars during the appeals process of his conviction would deprive him of his right to run for office.

Russian President Vladimir Putin has much more important matters on his hands than the fate of Edward Snowden, the U.S. intelligence leaker stranded for almost a month at a Moscow airport, the Kremlin said Friday.

"We have a lot to do. You've seen the working schedule of the president. These are much more important things than Snowden," Kremlin spokesman Dmitry Peskov told reporters, quoted by the ITAR-TASS news agency.

The conviction of Russian protest leader Alexei Navalny, his jailing and surprise release pending appeal were legal court decisions that should be respected, President Vladimir Putin's spokesman said Friday.

"Both things were done in accordance with the law," spokesman Dmitry Peskov said in the first Kremlin comment on the high-profile verdict, quoted by Russian news agencies.

Britain refused to hold a public inquiry into the poisoning of Russian dissident Alexander Litvinenko in part because of fears that it could damage ties with Russia, according to a letter published on Friday.

Interior minister Theresa May wrote to the coroner investigating the 2006 death of the ex-spy in London and explained that "international relations" were an issue in her decision, although they were not decisive.

A court in Russia's northern Kirov region on Friday ordered the release of protest leader Alexei Navalny pending the appeal against his five year sentence on embezzlement charges.

The court ruled that keeping Navalny in custody would deprive him of his right to stand in mayoral elections in Moscow on September 8. Navalny had been accepted as a registered candidate for the polls earlier this week.

The White House said Thursday it was "deeply disappointed" over the jailing of Russian protest leader Alexei Navalny on fraud charges, calling the proceedings "politically motivated."

White House spokesman Jay Carney called on Moscow to allow for a "fair" appeal in the case and to cease its "campaign of pressure" against Russia's opposition.

The last Soviet leader Mikhail Gorbachev on Thursday slammed the five year jail sentence handed to top Russian opposition leader Alexei Navalny, saying it was unacceptable to use courts to punish political opponents.

"I am convinced that using courts with the aim of fighting political opponents is unacceptable," Gorbachev said in a statement posted on the site of his charity. "Everything I know about this case... unfortunately confirms we do not have independent courts."

Jailed Russian opposition leader Alexei Navalny is pulling out of the Moscow mayoral race and is calling on his supporters to boycott the vote, his election chief said Thursday.

"A decision has been made to boycott the elections," Leonid Volkov told Agence France Presse, saying Navalny has decided to quit the race.

President Vladimir Putin on Wednesday said Moscow's relations with Washington outweighed the "squabbles" over a spying scandal revealed by U.S. fugitive Edward Snowden, who has applied for asylum in Russia.

"Relations between states are much more important than squabbles surrounding the work of security services," Putin was quoted as saying by the RIA Novosti news agency.