Russia's Foreign Ministry said Russian Foreign Minister Sergei Lavrov and US Secretary of State John Kerry called for a prompt start to the next round of Syria peace talks in a phone conversation on Friday.
The talks were originally due to begin on March 7 in Geneva, but have been postponed until March 9, due to " logistical and technical reasons and also for the ceasefire to better settle down," the UN said.
"The two sides called to start the negotiations as soon as possible ... between the Syrian government and the whole spectrum of the opposition, during which the Syrians themselves should determine the future of their country," the ministry said in a statement.
Kerry and Lavrov also emphasize the need for mutual cooperation to ensure the end of hostilities in Syria, the ministry said.
Syria is currently in a full blown civil war between five main factions - the regime, the opposition, Al Qaeda affiliate Nusra Front, DAESH, and the YPG militants.
US-Russian agreement for a cessation of hostilities in Syria came into effect on February 27, aiming to last for two weeks.