Fugitive U.S. intelligence leaker Edward Snowden was staring at the logistical nightmare of escaping Russia for a safe haven in Latin America on Sunday after three leftist leaders offered him asylum in their states.

Bolivia on Saturday became the third country to extend an offer of asylum to the 30-year-old former U.S. National Security Agency (NSA) contractor sanctuary after similar guarantees from Venezuela and Nicaragua.

A prosecutor on Friday asked a Russian court to convict an opposition leader of embezzlement and sentence him to six years in prison.

Alexei Navalny, who led protests against President Vladimir Putin and exposed alleged government corruption, is accused of heading a criminal group that embezzled 16 million rubles ($500,000) worth of timber from a state-owned company while working as an adviser to the provincial governor in Kirov in 2009.

Russian diplomats on Thursday held several hours of talks with a high-ranking North Korean official, urging Pyongyang to ramp up efforts to revive the stalled six-party nuclear negotiations.

"The Russian side stressed the need to unite efforts in the interests of easing tensions (and) creating conditions for the earliest resumption of the six-party talks," the foreign ministry said in a statement after top Russian diplomats met with North Korea's first vice foreign minister Kim Kye-Gwan.

Russia on Thursday blocked a U.N. Security Council demand that Syria allow immediate access to thousands of civilians trapped by a government offensive on the city of Homs, diplomats said.

Diplomats said Russia's opposition to the statement proposed by council members Australia and Luxembourg was a new sign of a growing international split over the 26-month old conflict.

Russia on Thursday called on all of Egypt's political forces to "exercise restraint" and refrain from violence, following the toppling of Islamist president Mohammed Morsi by the army.

"We consider it important for all political forces in Egypt to exercise restraint... to consider the broad national interests of their actions, and to prove that they strive to solve the brewing political and socio-economic problems in a democratic framework, without violence, and accounting for the interests of all social groups and religious confessions," the foreign ministry said in a statement.

Russia is suspending the launches of Proton rockets after an unmanned rocket carrier exploded on takeoff this week, a source on the Russian Baikonur cosmodrome in Kazakhstan said Thursday.

"The investigation commission that is looking into the causes of the accident on July 2 has made a decision to stop the preparations for the planned Proton rocket launches from Baikonur," the source told Interfax news agency.

Russian rescue teams on Wednesday found four survivors including a teenage boy when they finally reached the wreckage of a helicopter that crashed in the nearly impassable taiga of eastern Siberia the day before.

Three people have already been evacuated from the crash site, spokesman for the Emergencies Ministry, Oleg Voronov, told AFP, adding the fourth survivor was a teenage boy who is believed to have a broken spine.

Russia's top Islamist leader Doku Umarov called in a video released on Wednesday for jihadists to stage attacks against a range of targets that include the 2014 Sochi Olympic Games.

"We know that on the bones of our ancestors, on the bones of many, many Muslims who died and are buried on our territory along the Black Sea, today they plan to stage the Olympic Games. We, as the Mujahedeen, must not allow this to happen by any means possible," Umarov said in a message posted on the kavkazcenter.com website.

China and Russia will hold their second joint naval exercises on Friday, state media said, as Beijing and Tokyo row over disputed islands in the East China Sea.

The drills come as China's maritime power increases -- its first aircraft carrier went into service last year -- and as tensions escalate over island disputes with Japan and other neighbors.

U.S. Secretary of State John Kerry said he raised the sensitive issue of secrets leaker Edward Snowden in talks with his counterpart from Russia, where the U.S. fugitive is in diplomatic limbo.

But Kerry told reporters after an Asia security summit in Brunei that his discussions with Sergei Lavrov failed to yield any progress on an impasse that has further strained testy U.S.-Russian ties.