The United Nations Security Council has unanimously demanded all parties in the Syrian civil war comply with the terms of a US-Russian "cessation of hostilities" deal due to take effect at midnight local time (10pm GMT).
The demand also urged the Syrian government and opposition to resume UN-brokered peace talks.
Staffan de Mistura, the UN's mediator for Syria, told the 15-nation council he intended to reconvene peace talks on 7 March if the halt in fighting holds and allows for greater delivery of humanitarian relief.
If the ceasefire holds, it will mark the first period of relative quiet in Syria's five-year civil war.
"It is going to be extremely challenging, especially at the outset, to make this work," U.S. Ambassador to the United Nations Samantha Power told the council. "Even a partial de-escalation would make a real difference in the lives of Syrians."
She added that any violations of the cessation of hostilities must be met with a "sober, coordinated response."
All parties subject to the ceasefire agreement will still be allowed to launch operations against Isis, Jabhat al-Nusra and other UN-designated terror groups.
Russia denied squeezing in a final round of bombing attacks against civilians and rebels ahead of the ceasefire.
Additional reporting by Reuters
