US-Russian agreement on a cessation of hostilities has started to take effect at Saturday midnight local time (2200GMT).
The US and Russia have agreed on a draft to call for a cessation of hostilities in Syria to begin on Feb. 27.
The deal does not include DAESH, the Al Qaeda-linked Nusra Front and any other militias designated as terrorist group by the UN Security Council. Both the US and Russia continue to target those terrorist groups with air strikes in Syria.
Most major armed opposition groups in Syria indicated they were ready to participate in the plan to cease hostilities on Saturday, as long as the Syrian regime upholds its obligations under the deal, a senior Obama administration official said on Friday.
“We continue to consult closely with the major Syrian armed opposition groups across Syria, which, through the HNC and directly with us, have confirmed their acceptance of the terms of the cessation of hostilities," the official said.
UN's Syria mediator Staffan de Mistura said on Friday that he intends to reconvene Syrian peace talks on March 7 if the cessation of hostilities largely holds and allows for greater delivery of humanitarian relief.
De Mistura had abruptly aborted a first round of talks on Feb. 3 and urged countries in the International Syria Support Group (ISSG), led by the United States and Russia, to do more preparatory work.
The UN Security Council unanimously demanded on Friday that all parties to the civil war in Syria comply with the terms of the cessation of hostilities.
The council demanded "that all parties to whom the cessationof hostilities applies ... fulfill their commitments."
On Feb. 11, foreign ministers from 17 countries met in Munich agreed to implement a "cessation of hostilities" and to immediately accelerate and expand the delivery of humanitarian aid to besieged Syrian towns and villages.
That agreement called for a truce by Feb. 19, however the deadline was missed because Syrian regimes strongest ally Russia continued bombing targets in Syria.
The deal came days before United Nations peace talks in Geneva which are aimed at ending the five-year-long civil war in Syria.
The war has killed at least 470,000 Syrians and injured 1,900,000 others which made up nearly 11.5 percent of the Syrian population, according to a report which was released by the Syrian Centre for Policy Research on February 10.