Bombings and fighting broke out on Friday in Syria, violating a weekend-long peace pact between government forces and rebels to allow celebration of Muslim holiday Eid al-Adha.
A car bomb in the country's capital, Damascus, has reportedly killed at least five and injured 30 more, while government militia have allegedly been mortaring the city's suburbs, as well as other cities including Aleppo and Deir al-Zor.
The three-day truce, called for by peace envoy to the country Lakhdar Brahimi, lasted less than a day, as conflict broke out across the war-torn country.
The Syrian Observatory for Human Rights has claimed that some 150 people were killed in Friday's violence, including civilians, rebel soldiers and soldiers loyal to the president, Bashar al-Assad.
A Damascus rebel told Reuters: "The army began firing mortars at 7 a.m. I have counted 15 explosions in one hour and we already have two civilians killed.
"I can't see any difference from before the truce and now."
Friday's car bomb, which killed five, was detonated next to a playground in a residential area of Damascus. The makeup of the victims is not yet known.
The Assad regime blamed "terrorists" for the attack across the country.
The civil war has gripped the country for 19 months and killed a reported 35,000 people.