Russia and the United States agreed to put aside their differences over Syria and to try to convene international talks with both sides in the civil war to end the carnage that is inflaming the Middle East.
Prime Minister David Cameron said there is a "growing body of limited but persuasive information" showing that the Syrian regime has used chemical weapons including sarin.
There is a growing body of limited but persuasive information showing that the regime has used, and continues to use, chemical weapons including sarin. The room for doubt about this continues to diminish. We will continue to take action on every front, working with our allies, backing the opposition, pushing for a political solution.
There is an urgent need to start a proper negotiation to force a political transition and to bring this conflict to an end. I will be flying to Sochi on Friday to meet with President Putin to discuss this issue further.
– David Cameron
He said he had spoken with the US Secretary of State John Kerry on his return from Russia, and confirmed he will be meeting President Putin on Friday to discuss the crisis.
Russian Foreign Minister Sergey Lavrov said Russia was "no less concerned than the United States over the possible use of chemical weapons in Syria" as he pledged to hold an international peace conference to look for a political solution to the ongoing crisis in the country.
Speaking at a joint press conference with US Secretary of State John Kerry he said:
"Russia and the United States will encourage both the Syrian government and the opposition groups to look for a political solution.
"We have also agreed on the need to try and hold, as soon as possible, probably even at the end of this month, an international conference as a follow-up to the Geneva conference which took place in June last year in Geneva.
"We are no less concerned than the United States over the possible use of chemical weapons in Syria. This subject is extremely complicated and extremely responsible. One should be one hundred percent sure that we are not the captives of rumours or even deliberate provocations."
The United States and Russia have pledged to convene an international conference later this month on Syria's civil war, setting aside more than two years of differences on how to approach the conflict.
US Secretary of State John Kerry met with Russian President Vladimir Putin and Foreign Minister Sergey Lavrov for more than five hours yesterday in an attempt to agree how best to move President Bashar al-Assad's regime and rebels into talks on political transition.