The first major temporary truce in Syria’s five-year civil war has come into effect.
The “cessation of hostilities” began at midnight (22:00 GMT Friday) with early reports saying front lines were silent.
However, Syrian state media said several shells had hit residential areas of the capital, Damascus. It did not say who had fired.
Low-level clashes have also been reported between rebel groups and government forces elsewhere.
A special taskforce chaired by the United States and Russia is to meet in Geneva to monitor violations of the agreement.
The truce involves Syrian government and rebel forces, but not the so-called Islamic State group (IS) or the al-Qaeda-linked Nusra Front.
In the run-up to the deadline, US President Barack Obama warned the Syrian government and its ally Russia “the world will be watching”.
More than 250,000 Syrians have been killed in Syria’s civil war and millions more have been forced from their homes.
