Washington( CNN) Two days after world power agreed to a “cessation of hostilities” in Syria, prospects for its success are already being met with skepticism as bombs pelted Damascus suburbiums Friday and officials involved acknowledged the difficulties ahead.

Finer points of the deal are being worked out in Geneva by U.S.- and Russian-led task force that aim to rushed humanitarian aid to besieged areas and force a pause in the 5-year-old civil war within a week.

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