DAMASCUS - Rebels have killed 22 troops in the Syrian army's deadliest day of a three-week-old ceasefire deal, even as UN observers said they were having a "calming" effect as they deploy on the ground.
Fifteen troops, including two colonels, were killed in a rebel ambush at dawn in the northern province of Aleppo, said the Syrian Observatory for Human Rights.
Two rebels also died in the attack near Al-Rai village, after President Bashar al-Assad's forces had "scaled up military operations" there in the days since the truce took effect on April 12, said the watchdog. Clashes near Damascus killed seven soldiers and a rebel fighter, while the army shelled and torched activists' homes in eastern Deir Ezzor province, the watchdog said.
At least four civilians were also killed by army gunfire, including a woman who died in Deir Ezzor province and two civilians in Daraya near Damascus, where five soldiers were wounded the previous night.
Despite the bloodshed, the head of a UN military observer mission said his team was having a positive effect.
Major General Robert Mood brushed off criticism that the UN Supervision Mission in Syria, or UNSMIS, had been too slow to get off the ground and said their numbers would double within days.