The Syrian military has unilaterally declared a 72-hour truce covering the whole country, state media report.
A statement by the general command said the “regime of calm” began at 01:00 on Wednesday (22:00 GMT on Tuesday) and would last until midnight on Friday.
The period covers the Islamic festival of Eid al-Fitr.
Earlier, President Bashar al-Assad made a rare public appearance outside the capital, Damascus, attending Eid prayers in the devastated city of Homs.