Greek Prime Minister Alexis Tsipras on Wednesday called for an end to the "vicious cycle" of sanctions against Russia over Ukraine, while Russia's President Vladimir Putin denied using Athens to sow discord within the EU.

Putin and Tsipras hailed mutual ties after meeting in the Kremlin on the first of two days of the Greek premier's visit to Russia that is closely watched by the European Union amid its worst standoff with Moscow since the Cold War.

Hundreds of supporters of slain Russian opposition leader Boris Nemtsov gathered Tuesday at the site near the Kremlin where he was killed to commemorate his death. 

Friends and ex-colleagues of the murdered Kremlin critic held a "Minute of no silence" 40 days after he was gunned down on a central Moscow bridge.

A close ally of top Kremlin critic Alexei Navalny said on Wednesday he has been given political asylum in Britain after fleeing Russia over alleged political persecution.

Vladimir Ashurkov -- who was executive director of opposition leader Navalny's anti-corruption fund -- told Moscow's independent TV channel Dozhd that British authorities had approved a request he filed last year. 

Russian President Vladimir Putin and his Iranian counterpart Hassan Rouhani voiced hope Thursday for progress at crunch talks over Iran's nuclear drive, the Kremlin said. 

"Hope was expressed for success at the new round of talks in Lausanne," the Kremlin said in a statement after Rouhani called Putin to discuss the negotiations in Switzerland.

Germany on Friday criticized Russia for signing an alliance with Georgia's breakaway region South Ossetia this week, joining a chorus of Western condemnation.

"With this treaty, Russia once more puts into question Georgia's territorial integrity and sovereignty," German government spokeswoman Christiane Wirtz said.

Seventy years ago they crushed Nazi Germany together but raging tensions over Ukraine mean Russia's former World War II allies in the West will snub the Kremlin's showcase victory anniversary celebrations.

As top Western leaders give President Vladimir Putin's Red Square parade on May 9 the cold shoulder, the guest list of those likely to be coming -- including China's president and North Korea's reclusive leader -- shows how Moscow's international standing has shifted.

Russia said Thursday it had doubled the number of troops taking part in mass drills ordered by President Vladimir Putin this week to 80,000 in a major show of strength amid tensions with the West over Ukraine.

Putin on Monday ordered drills for more than 40,000 troops in regions spanning the country, from the Arctic to the far east to the volatile southern Caucasus, and ordered nuclear bomber jets to be deployed in Crimea a year after its annexation by Moscow.

Russian President Vladimir Putin on Wednesday triumphantly joined tens of thousands of supporters to mark one year since his takeover of Crimea, a seismic shift that shattered ties with Ukraine and the West.

Putin appeared on stage in front of a flag-waving crowd at a celebratory concert by the walls of the Kremlin to make an impassioned justification for seizing the Black Sea peninsula in a move that sent his poll ratings soaring.

Russia on Wednesday signed a wide-ranging alliance with Georgia's breakaway region of South Ossetia that will further cement its control over the territory despite fierce condemnation from the West.

President Vladimir Putin inked a deal in Moscow with South Ossetian leader Leonid Tibilov that officially makes Russia responsible for defending the self-declared republic, where the Kremlin has stationed thousands of troops since a war with Georgia there in 2008.

Russian President Vladimir Putin on Monday dismissed days of frenzied "rumors" over his health and whereabouts as he reappeared in public after an unusually long 10-day absence.

The feverish speculation fueled by social media saw all eyes turn to an otherwise unexceptional meeting planned between Putin and the leader of Kyrgyzstan to see whether the Russian strongman would appear.