At least 15 people were reported killed on Sunday in shelling by government and insurgent forces in northwestern Syria, further straining a Russian-Turkish ceasefire deal for the region.
Opposition fighters in the southern province of Daraa announced a ceasefire deal late on Friday with regime ally Russia.
Syrian rebel groups said on Saturday they would consider a ceasefire deal brokered by Russia and Turkey "null and void" if the Damascus government's forces and their allies continued to violate it.
Pro-Syrian government fighters opened fire on a convoy as it prepared to leave rebel-held eastern Aleppo on Thursday, wounding at least three people, a rescue service spokesman said.
Philippine President Rodrigo Duterte on Sunday rejected a demand by Maoist-led rebels to free more prisoners as part of a ceasefire deal, saying he had made enough concessions and was willing to let peace talks collapse if necessary.
The Philippine government and Communist guerrillas on Friday signed an indefinite ceasefire deal to facilitate peace talks aimed at ending one of Asia's longest-running insurgencies.
At least 27 civilians were killed in regime bombardment on rebel-held areas across Syria, a monitor and local sources said, in the latest deadly violence despite a ceasefire deal.