Damascus: The UN call for all sides to respect a ceasefire was rendered impactless as the violence in Syria claimed 26 lives on Tuesday.
Ten civilians killed by regime mortar fire and 12 troops died in clashes with rebels were among 26 dead.
UN chief Ban Ki-moon said it was vital that government and opposition alike cooperate fully with a hard-won UN observer force as it fans out in its mission to shore up the ceasefire agreement that took effect on April 12.
But despite his appeal, human rights monitors reported no let-up in the violence, a day after a series of blasts condemned by Ban as "terrorist bomb attacks" killed more than 20 people.
Nine members of a single family were among the 10 killed in the regime bombardment of a village in northwestern Idlib province, said the Syrian Observatory for Human Rights.
A mortar round slammed into their home in Mashmashan village near the town of Jisr al-Shughur, the watchdog said, adding four women and two children were among the dead.
Elsewhere in the same province, random gunfire killed a 13-year-old boy in the town of Maaret al-Numan.
Outside Damascus, gunfire from a minibus belonging to the security forces killed an 80-year-old man in the town of Qatna, while regime shelling killed a civilian in a village of central Hama province, said the Observatory.
In Deir Ezzor province in the northeast, 12 soldiers were killed in clashes with rebel fighters, said the watchdog.
One civilian was also killed during the fighting in the Busayra area of the province, in which troops responded with missile and heavy machinegun fire, it added.=