Fierce clashes between Syrian government forces and rebels have broken out in several regions across the country, in violation of a ceasefire, an activist group said. 

"The ceasefire has collapsed in several regions of Syria but there is stillless violence and fewer victims than usual," Rami Abdel Rahman, the head of the Syrian Observatory for Human Rights director, told the AFP news agency on Friday.

The fighting started around a military base near Maaret al-Numan, a strategic opposition-held town in the country's north.

"Violent clashes started around 0730 GMT around the Wadi Deif base. The army responded by bombing the neighbouring village of Deir Sharqi. It is the first violation of the ceasefire," Abdul Rahman said. 

He said that among the rebel fighters were members of the Islamist Al-Nusra Front, an armed group that had already indicated it would not abide by the truce, agreed by President Bashar al-Assad's government and the main rebel Free Syrian Army (FSA) for the four-day Muslim holiday of Eid al-Adha.

Fighting also reportedly took place in the capital Damascus, in the city of Homs and Aleppo province.

There were no immediate indications from either the regime or the FSA that they considered the ceasefire had been violated.

Protests

Meanwhile, anti-regime protests erupted across Syria on Friday, activists said. The protests after morning prayers to mark the start of Eid al-Adha came as the ceasefire took effect.

The Syrian Observatory for Human Rights said protests had taken place in the northeastern city of al-Raqqa, where security forces fired tear gas, and in the southern Deraa province, where three people were injured as police fired live rounds to disperse demonstrators.

Activists said 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 al-Assad: "Traitor, give up, you have destroyed Syria".

In the Deraa provincial town of Dael, about 100 demonstrators were seen chanting anti-regime slogans on the main square, in a video activists posted on the Internet.