By Louis Charbonneau and Michelle Nichols
UNITED NATIONS (Reuters) - The United Nations Security Council on Friday unanimously demanded that all parties to the civil war in Syria comply with the terms of a U.S.-Russian deal on a "cessation of hostilities" due to take effect at midnight local time (2200 GMT).
The demand was included in a resolution drafted jointly by Russia and the United States that also urged the government and opposition to resume U.N.-brokered peace talks.
Before the 15-nation council voted, U.N. Syria mediator Staffan de Mistura told its members via video link from Geneva that he intends to reconvene peace talks on March 7 provided the halt in fighting largely holds and allows for greater delivery of humanitarian relief.
The council demanded "that all parties to whom the cessation of hostilities applies ... fulfill their commitments."
It also urged "all Member States, especially ISSG (International Syria Support Group) members, to use their influence with the parties to the cessation of hostilities to ensure fulfillment of those commitments and to support efforts to create conditions for a durable and lasting ceasefire."
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.
"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."
Russian Deputy Foreign Ministry Gennady Gatilov told the council that "we now have a real chance to end violence and to step up our collective combat against terrorism." He added that it would also be an opportunity to boost humanitarian aid relief.
The council meeting was delayed by half an hour as the United States and Russia engaged in last-minute negotiations on the text, diplomats told Reuters.
Among the changes was the removal of two references to the Saudi-backed High Negotiations Committee (HNC), a Syrian opposition coalition that Russia and Iran do not consider to be a legitimate representative in the peace talks.
(Reporting by Michelle Nichols and Louis Charbonneau; Editing by Andrew Hay)