The United Nations is accelerating deployment of unarmed observers to Syria to ensure all 300 are on the ground by the end of May to monitor a shaky ceasefire.

UN peacekeeping chief Herve Ladsous said that observers had reported violations of the truce by both Syrian President Bashar al-Assad's security forces and opposition groups.

There are currently 24 observers on the ground as part of the UN Supervision Mission in Syria.

The ceasefire brokered by UN-Arab League envoy Kofi Annan briefly calmed but failed to halt the conflict.

Violence erupted in two Syrian provinces today.

A rights group reported that 10 civilians were killed in an army mortar attack and 12 soldiers killed in a fire-fight with rebel gunmen.

The Britain-based Syrian Observatory for Human Rights said nine members of one family died in mortar bomb blasts in a village in the northern province of Idlib.

Reports from Syria cannot be independently verified as state authorities have barred international journalists and rights groups.

The UN says Syrian forces have killed more than 9,000 people since the uprising began in March 2011.

Its special envoy for children in war zones said more than 34 children were believed to have been killed since the UN-backed ceasefire nominally came into force on 12 April.

Like other Arab revolts against autocratic rulers, Syria's uprising began with peaceful protests but a violent government response has spawned an increasingly bloody insurgency.

Damascus says rebels have killed more than 2,600 soldiers and police, and the speaker of Syria's parliament, Mahmoud al-Abrach, said outside states backing the insurgency bore responsibility for the bloodshed.