Fierce clashes between Free Syrian Army and Asasdites broke out in several regions across the country.
The fighting started around an Assadite military base near Maaret al-Numan, a strategic liberated town in the country's north.
Violent clashes started around 0730 GMT around the Wadi Deif base. The Assadites responded by bombing the neighbouring village of Deir Sharqi.
Freedom fighters were members of the Islamic Al-Nusra Front that had already indicated it would not abide by the truce, agreed by Assad's government and the main Free Syrian Army (FSA) for the four-day Muslim holiday of Eid al-Adha.
Fighting also took place in the capital Damascus, in the city of Homs and Aleppo province.
There were no immediate indications from either the Assadites or the FSA that they considered the ceasefire had been violated.
Meanwhile, anti-Assad's protests erupted across Syria on Friday. The protests after morning prayers to mark the start of Eid al-Adha came as the ceasefire took effect.
Protests had taken place in the northeastern city of al-Raqqa, where Assadites fired tear gas, and in the southern Deraa province, where three people were injured as Assad's police fired live rounds to disperse demonstrators.
Demonstrations also took place in the capital Damascus and its suburbs, in the country's largest city of Aleppo, the eastern province of Deir Ezzor and in the northwestern province of Idlib.
In the village of Al-Habit in Idlib province, protesters chanted against Assad: "Traitor, give up, you have destroyed Syria".
In the Deraa provincial town of Dael, about 100 demonstrators chanted anti-regime slogans on the main square.