Air strikes on a camp housing Syrians uprooted by war have killed 28 people near the Turkish border, according to a monitoring group, while fighting raged in parts of northern Syria despite a temporary deal to cease hostilities in the city of Aleppo.
The British-based Syrian Observatory for Human Rights said the dead included women and children and the death toll from the airstrikes, which hit a camp for internally displaced people near the town of Sarmada, was likely to rise.
Footage shared on social media showed rescue workers putting out fires which still burned among charred tent frames, pitched in a muddy field.
"There were two aerial strikes that hit this makeshift camp for refugees who have taken refuge from fighting in southern Aleppo and Palmyra," an activist from the nearby town of Atmeh who spoke to people near the camp said.
An opposition civilian aid official who lives about 1km from the camp, said around 50 tents and a school had burned down.
The United States said the victims were innocent civilians who had fled their homes to escape violence.
"These individuals are in the most desperate situation imaginable, and there is no justification for carrying out military action that's targeting them," spokesman Josh Earnest said.
Sarmada lies about 30km west of the city of Aleppo, where a cessation of hostilities brokered by Russia and the US had brought a measure of relief.
However fighting continued nearby and President Bashar al-Assad said he still sought total victory over rebels.
Syrian state media said the army would abide by a "regime of calm" in Aleppo that came into effect overnight for 48 hours, after two weeks of death and destruction.
The army blamed Islamist insurgents for violating the agreement overnight, saying they had shelled government-held residential areas of divided Aleppo indiscriminately.
Residents said the violence eased by morning and more shops opened up.
Heavy fighting was reported in the southern Aleppo countryside near the town of Khan Touman, where al Qaeda's Syrian branch Nusra Front is dug in close to a stronghold of Iranian-backed militias, a rebel source said.
Rebels were attacking government positions around the town and government forces carried out air attacks on the area, pro-Syrian government television channel Al-Mayadeen and the Observatory said.
In the east of the country, so-called Islamic State militants captured the Shaer gas field, their first gain in the Palmyra desert area since they lost the ancient city in March, according to rebel sources and a monitor.
Amaq, an IS-affiliated news agency, said IS militants killed at least 30 Syrian soldiers stationed at Shaer and seized heavy weapons, tanks and missiles.
Assad seeking 'final victory'
Mr Assad has said he would accept nothing less than an outright victory in the five-year-old conflict against rebels across Syria, state media reported.
In a telegram to Russian President Vladimir Putin thanking Moscow for its military support, he said the army was set on "attaining final victory" and "crushing the aggression".
The Observatory and a resident reported rebel shelling of the government-held side of Aleppo, which was Syria's commercial hub and largest city before the war.
But a resident of the rebel-held eastern part of the city said that although warplanes flew overnight, there were none of the intense raids seen during the past 10 days.
People in several districts ventured onto the streets.
A rebel source also said that despite intermittent firing across the city's front lines, fighting had subsided and no army shelling of residential areas had been heard.
