Some 600 Russians and Europeans are fighting alongside Syrian rebels against President Bashar Assad's regime, Russian President Vladimir Putin said Friday, warning the West against arming the opposition.

"At least 600 people originating from Russia and Europe are fighting on the side of the Syria opposition," Putin told the Saint Petersburg Economic Forum.

President Vladimir Putin urged lawmakers Friday to pass a newly-drafted bill that would grant an amnesty to white-collar criminals in a bid to improve Russia's frigid business climate at a time of slowing growth.

In a keynote address to the Saint Petersburg International Economic Forum, Putin also unveiled a $13.7-billion stimulus package designed to help Russia spend its way out of an economic slump that threatens to reach recession by the end of the year.

Russian security services sought Thursday to unravel a mystery after a fraudster managed to fool the country's news agencies into believing one of President Vladimir Putin's closest allies had been "fired" from his post.

The purported dismissal of Vladimir Yakunin as head of Russian Railways (RZD) was flashed by Russia's three main wires on Wednesday after they had received an emailed statement looking very much like an official government press release.

President Barack Obama said Russian and U.S. nuclear weapons should be slashed by up to a third in a keynote speech in front of Berlin's iconic Brandenburg Gate in which he called for a world of "peace and justice".

Obama used the once divided city's rebirth as a metaphor for progress, as he stood on the east side of the route of the Berlin Wall, and warned the "complacent" West that history did not stop with its Cold War victory.

U.S. President Barack Obama will on Wednesday propose the United States and Russia cut strategic nuclear warheads by a third and reduce tactical nuclear arsenals in Europe, a U.S. official said.

Obama, who will make the proposals in a major speech in Berlin, will also commit to attending a nuclear security summit in The Hague next year, and to holding a similar meeting in the final year of his presidency in 2016.

President Vladimir Putin said Tuesday that Russia would not rule out sending fresh arms to the Syrian regime and warned the West against arming "criminals" in the rebellion.

"If we conclude such contracts, then we will deliver on such contracts," he told reporters after a G8 summit in Northern Ireland.

Russia and the U.S. have not abandoned hopes of holding a Syria peace conference, Russian President Vladimir Putin said after meeting his U.S. counterpart Barack Obama on Monday.

Putin told Obama that their positions on Syria do not coincide but both leaders agree on the need to push for negotiations in Syria's two-year-old civil war, the Associated Press reported.

Russian President Vladimir Putin on Sunday insisted that Moscow had abided by "rules and norms" when providing weapons to Syria and demanded other G8 countries which are contemplating arming rebels do likewise.

Putin was speaking in London after holding talks with British Prime Minister David Cameron which could set the tone for the G8 summit, with the West at odds with Moscow over the conflict.

Russian President Vladimir Putin on Sunday congratulated Hassan Rowhani on his victory in Iran's presidential election and urged him to forge closer ties with Moscow.

"Putin expressed confidence that Hassan Rowhani's work on this high post will promote the flourishing of (Russian) friend Iran and further strengthen Russian-Iranian relations," the Kremlin quoted Putin as saying in a message to Iran's president-elect.

Russian President Vladimir Putin and U.S. President Barack Obama will hold a bilateral meeting at the G8 summit in Northern Ireland after Washington upped the ante in the Syrian war by pledging military aid to rebels, the Kremlin's foreign policy aide said.

Putin and Obama will meet on the sidelines of the G8 summit at the Lough Erne resort on Monday and will also kickstart a Syria session at the summit at the request of host Britain.