The UN Security Council has adopted a resolution demanding a 30-day cease-fire across Syria "without delay" to allow aid deliveries and medical evacuations.
All 15 members of the council voted on February 24 in favor of the cessation of hostilities following a flurry of last-minute negotiations on the text.
Reports said the resolution's sponsors, Kuwait and Sweden, amended the text to get Russian support, dropping a demand that the truce take effect in 72 hours.
Russia, a key ally of Syrian President Bashar al-Assad, has veto power on the security council.
The vote comes as Syrian government forces killed more than 500 civilians during a week of intense bombardment in eastern Ghouta, a rebel-held enclave near the capital, Damascus, according to activists.