Most fighting stopped across western and northern Syria on Saturday under a cessation of hostilities which the United Nations called the best hope for peace since civil war began five years ago.
The U.S.-Russian accord accepted by President Bashar al-Assad's government and many of his opponents, agreed that fighting should cease so essential aid can reach civilians.
A lull in gunfire and shelling was reported around Damascus, the capital, and the northern city of Aleppo, which has seen an intense bout of fighting between government forces, supported by Russian airstrikes, and rebels in the area.
Moscow’s air strikes are aiding President Bashar al-Assad’s attempts to reclaim parts of the country that his government lost control of during the five-year-old civil war. However the Russian military agreed to suspend all flights over Syria on Saturday.
"Russia's air force fully halted bombing in the green zone - that is in those areas and those armed groups which had sent us ceasefire requests," Lt-Gen Sergei Rudskoi, a senior representative of the General Staff, told reporters.
Rudskoi said Russia will continue airstrikes against Islamic State group strongholds although it was keeping its aircraft on the ground for now "to avoid any possible mistakes".
The U.N. Security Council unanimously passed a vote late on Friday to support the pause in fighting in Syria, and demanded that all parties fulfill their commitments to end hostilities.
"Let's pray that this works because frankly this is the best opportunity we can imagine the Syrian people has had for the last five years in order to see something better and hopefully something related to peace," U.N. Syria envoy Staffan de Mistura said at a midnight news conference in Geneva.
The deal ushered through by the U.N. Security Council has not been directly signed by the Syrian warring parties and is less binding than a formal ceasefire. There have been claims of violence since the truce was put into place.
Syria's state media said several shells hit a residential suburb in Damascus on Saturday and at least two people were killed and several wounded when a car bomb exploded at the entrance of Salamiya, a town east of Hama city and a front-line between government forces and Islamic State group. The Syrian Observatory for Human Rights which monitors the conflict said it was carried out by Islamic State group.
The U.N. says over 400,000 people are trapped and in need of emergency assistance in 15 locations. The war has killed more than 250,000 people and has displaced 11 million people.
VIDEO: From the Front Lines in Syria