British Prime Minister David Cameron and Russian President Vladimir Putin on Friday discussed joint options for ending the crisis in Syria amid a new diplomatic push to resolve the two-year conflict.

Cameron's rare call on Putin at his summer vacation residence in the Black Sea resort of Sochi came three days after top U.S. and Russian diplomats agreed to make a joint effort in search of a solution.

Russian Prime Minister Dmitry Medvedev on Thursday appointed former Kremlin foreign policy adviser Sergei Prikhodko as the head of his government's administration following the sudden departure of Deputy Prime Minister Vladislav Surkov.

Prikhodko worked as Medvedev's foreign policy adviser when he served as president between 2008 and last year.

U.S. President Barack Obama will meet British Prime Minister David Cameron at the White House on Monday to discuss Syria and the G8 summit next month in Northern Ireland, officials said.

"The prime minister's visit underscores the special relationship between the United States and the United Kingdom that has been crucial in advancing our shared security and prosperity," a White House statement said.

U.N.-Arab League envoy to Syria Lakhdar Brahimi on Wednesday "warmly welcomed" an agreement between the United States and Russia to pressure both sides in Syria to end the bloodshed, a statement from his office said.

"This is the first hopeful news concerning that unhappy country in a very long time," it said. "The statements made in Moscow constitute a very significant first step forward. It is nevertheless only a first step."

Russia and the United States agreed at top-level talks on Tuesday to push both the Syrian regime and rebels to find a political solution to their conflict and to hold an international peace conference, the Russian foreign minister said.

"We agreed that Russia and the United States will encourage both the Syria government and opposition groups to find a political solution," Foreign Minister Sergei Lavrov said after talks with U.S. counterpart John Kerry in Moscow.

U.S. Secretary of State John Kerry arrived in Moscow Tuesday for talks with Russian President Vladimir Putin, seeking to restore frayed U.S.-Russia ties and win Moscow's support on the war in Syria.

Kerry is making his first trip to Russia since taking over as the chief U.S. diplomat in February, on what is one of his most diplomatically delicate missions to date.

Thousands of protesters on Monday filled a square in central Moscow to denounce Russian President Vladimir Putin one year into his new Kremlin term, as the opposition seeks to recover the momentum of their challenge to his rule.

Organizers said tens of thousands attended the rally, which marks one year since a chaotic May 6, 2012 anti-Kremlin protest that descended into violence, and Putin's return to the presidency a day later. Police estimated the numbers at 7,000.

Russian President Vladimir Putin held telephone talks with Israeli Prime Minister Benjamin Netanyahu over the Syrian conflict, the Kremlin said Monday, after Israel launched air strikes inside Syria.

Putin and Netanyahu discussed the "situation in the region and the situation around Syria," the president's spokesman Dmitry Peskov said in a statement to Russian news agencies, without giving further details. The Russian foreign ministry had earlier expressed concern over the air strikes.

About a thousand Muscovites rallied Sunday in memory of a bloody protest one year ago in which more than 400 were detained after showing their frustration with Vladimir Putin's return to the presidency.

The "Spring March of Freedom" was held almost a year to the day since Russian authorities deployed baton-wielding interior ministry troops to disperse a crowd of tens of thousands on the eve of Putin's May 7 swearing-in ceremony.

President Vladimir Putin on Wednesday handed out the first "Hero of Labor" awards to Russians since reviving the Soviet-era tradition this year, with recipients ranging from top conductor Valery Gergiev to a Siberian coalminer.

The honorary Hero of Labor award and medal, recreated by the Kremlin in March for the first time since the end of the Soviet Union, was bestowed on a group of five people for the first time as Russia marked the May 1 holiday with organized parades of labor unions and pro-Kremlin politicians.