A nationwide cease-fire brokered by the United States and Russia is mostly holding across Syria, the Syrian Observatory for Human Rights said on Tuesday.
Some air attacks and shelling were reported in the first hours of the truce on Monday evening, in areas including the north Hama countryside, East Ghouta and north of Aleppo, the monitoring body said.
But that appeared to die down and the Observatory said it had not recorded a single civilian death from fighting in the fifteen hours since the cease-fire came into effect at 7 p.m. (1600 GMT) on Monday.
Syrian state media said armed groups had violated the truce in a number locations in Aleppo city on at least five occasions since the early hours of Tuesday. The latest reported violation was at 0945 which was a mortar fired in southwest Aleppo.
The Observatory said pro-government forces during Tuesday had shelled near two villages in the south Aleppo countryside and had also shelled the Jobar neighborhood on the outskirts of Damascus. No injuries or deaths were reported.
The Observatory also said rebels had opened fire on the outskirts of a town in the west Hama countryside.
The cease-fire marks the second attempt this year to halt Syria's five-year-old civil war. Russia is a major backer of Syrian President Bashar al-Assad, while the United States supports some of the rebel groups fighting to topple him.
The truce does not cover the jihadist groups Islamic State or Jabhat Fateh al-Sham, a group formerly called the Nusra Front which was al-Qaida's Syria branch until it changed its name in July.
Fighting had raged on several key fronts before the cease-fire, including Aleppo and the southern province of Quneitra on Monday, the first day of the Eid al-Adha Muslim holiday.
The Observatory said at least 31 were killed by airstrikes on rebel-held Idlib province and eastern Damascus, and by bombardment of villages in the northern Homs countryside and rocket attacks in the city of Aleppo on Monday, before the truce.