A suspected female suicide bomber blew herself up on a bus packed with students in southern Russia on Monday, killing six people and raising security fears less than four months before the Winter Olympics.

The attack in the Volga River city of Volgograd, which also injured more than 30 people, was the deadliest outside the volatile North Caucasus in the past three years.

U.S. intelligence leaker Edward Snowden says he did not bring any secret documents with him to Russia when he fled there, ensuring Moscow had no access to the files.

In an interview with The New York Times published Thursday, Snowden said he gave all the classified papers he had obtained to reporters he met in Hong Kong before flying to Moscow, where he later secured asylum.

A senior Dutch diplomat at the Netherlands embassy in Moscow was beaten up at his home in the Russian capital by unknown attackers who scrawled the letters "LGBT" on a mirror, officials said Wednesday.

The incident comes amid growing tensions between Russia and the Netherlands over the arrest by the Russian authorities of the 30 crew of a Dutch-flagged Greenpeace ship campaigning against oil drilling in the Arctic.

The Moscow authorities on Monday scrambled to calm inter-communal tensions after the Russian capital was rocked by some of its worst ethnically-fueled rioting in years, sparked by the killing of a Russian allegedly by a Muslim migrant from the Caucasus.

Seeking to avert further protests, Moscow police detained 1,200 people in a raid on migrants as officials vowed to crack down on vegetable wholesale markets in the capital which employ hundreds illegally.

Russian protest leader Alexei Navalny on Thursday sent a car-load of complaints to court contesting the results of Moscow's mayoral election, as President Vladimir Putin was due to attend the inauguration of his ally as city chief.

Incumbent mayor Sergei Sobyanin, a Kremlin ally who barely avoided a run-off in Sunday's closer-than-expected vote, is due to be sworn in for a new term Thursday evening in front of hundreds of guests led by Putin.

The United States said Monday it would welcome a plan for Syria to hand over its chemical weapons but expressed skepticism at the Russian initiative, which is designed to head off American air strikes.

However, the U.S. Senate announced later on Monday that it will hold a procedural vote Wednesday on a measure authorizing President Barack Obama to use military force against Syria.

With a macho handshake, wide smiles for the cameras and a spot of small talk about the late summer weather, President Barack Obama and Russian counterpart Vladimir Putin sought Thursday to mask months of tensions that gave rise to talk of a bitter personal animosity.

The squirmingly awkward pictures from their last encounter at the G8 in June and Obama's cancellation of a bilateral summit in Moscow had created expectations of another tense encounter.

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.

An horrific accident that left 18 people dead and at least 40 injured outside Moscow was caused when a gravel truck smashed a bus full of passengers into two pieces, officials said.

The emergencies ministry had raised the death toll to 18 after several badly injured victims died in hospital.

Russia will meet a delegation from North Korea next week to discuss a possible resumption of talks about ending Pyongyang's nuclear program, the foreign ministry said according to a Russian news agency.

A top North Korean envoy, Vice Foreign Minister Kim Kye-Gwan, will travel to Moscow on Thursday for "consultations on the entire set of issues surrounding the North Korean nuclear program," the foreign ministry was quoted as stating by the RIA Novosti news agency.