A truce, brokered by the United States and Russia, was holding on Tuesday in Syria despite minor breaches, a monitoring group reported.
The Syrian Observatory for Human Rights added that the truce, which went into effect Monday at 7pm (1600 GMT), continued in most parts of the war-wracked country.
"In the first hours of the ceasefire, we registered some breaches," the Observeratory head, Rami Abdel-Rahman, told dpa.
"But since midnight, there have been no breaches. We have not documented any civilian casualty either. I think this is a good start of the ceasefire," he added.
Pre-midnight air raids were carried out in some rebel-held areas in the central Hama province, said the Britain-based Observatory, which relies on a network of activists inside Syria.
The watchdog also reported clashes between the Islamic State extremist militia and rival insurgents in the area of al-Qalamun on the rural outskirts of the capital Damascus.
No casualties were given.
The current ceasefire excludes Islamic State and al-Qaeda-affiliated militants.
Calm was also prevailing on Tuesday in Aleppo, a major battleground in Syria's five-year conflict, local activist Abdel-Mouneim Juneid said.
"The night was quiet for the first time in months. We have not heard any plane flying or strikes," Juneid told dpa via Facebook.
On Friday, the US and Russia sealed an ambitious agreement on Syria that also envisages unprecedented military coordination against militant groups there.
The truce is the second this year brokered by Washington and Moscow.
A ceasefire came into effect in Syria in February, but did not hold for long.