British Foreign Secretary Philip Hammond says the conflict in Syria will continue unless Russia and Iran use their influence on Syrian President Bashar al-Assad to reach a political solution.
Hammond, speaking to Parliament's Foreign Affairs Committee on September 9, said Britain might be prepared to accept Assad remaining in office during a transition period if it helped end the crisis.
Britain had previously demanded that Assad leave office.
Hammond added that any solution to the crisis -- now in its fourth year -- would have to be political rather than military.
"Essentially this is going to have to be a decision made by the sponsors of the key players in Syria, and in particular Iran and Russia deciding to call the shots with the Assad regime," he said.
Hammond said Russian and Iranian leaders "can make a phone call" to Damascus "tomorrow...and change the future of this situation."
Iran and Russia are two of Assad's biggest supporters.
More than 220,000 people have been killed and millions displaced by the fighting in Syria.
Based on reporting by Reuters