No civilian deaths recorded from fighting since ceasefire brokered by US and Russia began on Monday night
A nationwide ceasefire was holding across Syria at the start of its second day on Tuesday, the Syrian Observatory for Human Rights said.
The monitoring body said it had not recorded a single civilian death from fighting in the fifteen hours since the ceasefire came into effect on Monday night.
The seven-day truce, brokered by Russia and the United States, is their second attempt this year by 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 ceasefire is the boldest expression yet of hope by the administration of US President Barack Obama that it can work with Russian President Vladimir Putin to end the war. All previous diplomatic initiatives have collapsed in failure.
The Obama administration opposes Assad but wants to shift the focus of fighting from the multi-sided civil war between Assad and his many foes to a campaign against ISIL, an ultra-hardline jihadist group that controls swathes of Syria and neighbouring Iraq.
The ceasefire deal is backed by foreign countries ranging from Assad's ally Iran to Turkey, one of the main supporters of groups fighting to overthrow him.
But maintaining the ceasefire means overcoming big challenges, including separating nationalist rebels who would be protected under it from jihadist fighters who are excluded.