British Prime Minister David Cameron is set to call for a new diplomatic drive to end Syria's civil war as he is scheduled to meet world leaders at the UN in New York on Sunday.
According to sources, Cameron is expected to hold a series of meetings with other leaders - including US President Barack Obama - to argue that a peaceful solution will require a different leadership which the whole country can unite around, BBC reported.
He is expected to insist that Syrian President Bashar al-Assad stands down to allow reconciliation.
"Our view is very clear, Islamic State and Assad are both the enemies of the Syrian people," a senior British official said.
"The prime minister's view is still very clearly that in the endgame you need a different leader to build a peaceful and inclusive Syria."
British officials also warned finding a solution to the four-year conflict had been made more complicated by Russian military build-up in support of Assad's regime.
Russia is reported to have moved warplanes, helicopters, tanks, drones, artillery and troops into a military airbase near Latakia and the seaport of Tartus in recent weeks.
Meanwhile, French Foreign Minister Laurent Fabius told the General Assembly that President Assad should not play a role in Syria's future.
He said Western countries would be exposing themselves to failure if they told Syrians their future lay with Assad.
On Thursday, German Chancellor Angela Merkel said Assad should be involved in peace talks, but Fabius urged a united European strategy against such involvement.
