The leaders of Russia, France and Germany agreed Sunday to speed up their "exchange of information" over Syria.
The Security Council on Saturday adopted a resolution calling for a 30-day ceasefire in Syria 'without delay', to allow for aid deliveries and medical evacuations.
Syrian regime forces were engaged in heavy fighting with rebels in southern areas of opposition-held Eastern Ghouta on Sunday, a day after a UN call for a ceasefire
Ankara last month launched a military operation against the Kurdish People's Protection Units (YPG) militia in the western enclave of Afrin in northern Syria.
The two main groups controlling Syria's rebel enclave of Eastern Ghouta have welcomed a UN Security Council demand for a ceasefire, but vowed to fight back in case of renewed attacks.
Regime air strikes and artillery have been pounding the enclave near Damascus since February 18, with at least 519 dead since the bombing campaign was launched.
With Russia's backing, the council voted unanimously to demand the truce "without delay" as Syrian war planes pounded the rebel-held enclave of Eastern Ghouta.
"The resolution demands a cessation of hostilities "without delay" throughout Syria to allow the "safe, unimpeded and sustained" deliveries of aid and evacuations of the sick and wounded.
France and Germany have pushed for Russian support for the Syria ceasefire, which is mainly to allow aid to reach the besieged area and allow evacuations.
UN Security Council postponed the vote, for a month-long ceasefire, until 1700 GMT on Saturday as Western powers bickered with Russia over the wording.
Negotiations have run into problems over a key provision of the text that specifies when the ceasefire will begin.
UN Security Council will vote on a draft resolution demanding a 30-day ceasefire in Syria to allow for deliveries of humanitarian aid and medical evacuations.