Russian President Vladimir Putin has been playing host to an increasingly long queue of statesmen trying to stop the bloodshed in Syria.
The latest to arrive is Ban Ki-moon, UN secretary-general, who held meetings on Friday and is due to meet the Russian president.
So far, Putin shows no sign of abandoning President Bashar al-Assad, a staunch Russian ally.
Al Jazeera's David Chater, reporting from Moscow, says Putin "will not sacrifice such a vital strategic partnership, no matter what weight of international pressure is applied".
Russia is opposed to any armed by Text-Enhance">intervention by the West in Syria.
A day earlier on Thursday, US President Barack Obama and Turkish Prime Minister Recep Tayyip Erdogan pledged to increase pressure on Syria's President Bashar al-Assad to step down.
Obama said in a news conference with Erdogan at the White House on Thursday that the only way to resolveSyria's two-year crisis was for Assad to hand over power to a transitional government.
He said Turkey would by Text-Enhance">play a critical role in that process "We're going to keep increasing the pressure on the Assad regime and working with the Syrian opposition,'' Obama said. "We both agree that Assad needs to go.''
The leaders said that they had made Syria top of their agenda, as they agreed that the issue of chemical weapons was an important one and Obama said that the use of chemical arms should always be out of bounds.