The death toll increased to nine as Russian jets continued bombing camps near Syria's northwestern city of Idlib on Sunday in a flare-up of attacks on the last opposition-held bastion, witnesses and rescuers said.
Warplanes flying at high altitudes, aided by Syrian regime artillery, also dropped bombs on forests near the makeshift camps west of Idlib, witnesses said.
No immediate comment was available from Russia or its allies in the Syrian regime forces, which says it targets the hideouts of insurgent groups and denies attacking civilians.
The Syrian Civil Defense group said three children and a woman were among those killed in the strikes on the crowded camps where more than 70 people were wounded and rushed to field hospitals.
"There are no military bases or warehouses or opposition barracks here. Only civilians," Seraj Ibrahim, a rescuer with the Western-backed White Helmets organization, said when reached by phone.
More than 4 million people live in the densely populated opposition-held northwest area along the Turkish border. Most of them were driven there by successive Russian-led campaigns that regained territory seized by the opposition.
Opposition sources said a coalition of armed opposition groups retaliated by attacking several major Syrian regime outposts in the region.
Regime air forces struck a drones facility and a militant training camp in northwest Syria in response to earlier attacks by armed insurgents, Russia's state-owned news agency Tass reported on Sunday. Syrian state media did not report any fighting.
The Russian Defense Ministry on Friday said it had information that insurgents it describes as terrorists operating in the Idlib region were plotting an attack on the main Russian air base of Hemeimeem in the coastal province of Latakia with the use of unmanned suicide drones.
Russian jets last month hit areas under the control of Hayat Tahrir al-Sham after a bout of fighting among rival opposition forces in the northwest in renewed strikes that shattered a relative lull in raids since earlier this year.
Syrian leader Bashar Assad's regime and its ally Russia have regularly targeted hospitals and civilian areas since the start of the war in 2011.
The Idlib region is one of the last pockets to oppose Damascus. For years, the Assad regime has ignored the needs and safety of the Syrian people, only eyeing further territory gains and crushing the opposition. With this aim, the regime has for years bombed civilian facilities such as schools, hospitals and residential areas, causing the displacement of almost half of the country's population.
A fragile truce brokered nearly three years ago between Russia and Türkiye, which supports opposition groups, ended the fighting within a few months.
More than a million people have fled the Assad regime’s offensive yet it still frequently carries out attacks on civilians, hindering most from returning to their homes and forcing them to stay in makeshift camps.
With the help of Russia and Iran, Assad has turned the tide of a war that has lasted more than a decade and regained most of the territory he lost to rebels.
Syrian opposition condemns the attack
The Syrian Opposition Coalition and the Syrian Interim Government both condemned the shelling of the camp in statements released early on Monday.
"The regime has dangerously increased violence with its latest attacks," the coalition warned in its statement. "The Assad regime’s said attack constitutes a war crime," it argued and accused the international community of remaining silent in the face of the regime’s violations.
The opposition called for the United Nations Security Council (UNSC) to assemble an emergency meeting in order to determine measures that will "see those committing war crimes deservedly punished."
The interim government too said they wanted attacks targeting civilians to "end immediately" and urged the international community to act against the Assad regime and its allies.
"Failure to hold those committing war crimes and crimes against humanity accountable will only encourage killers worldwide to shed blood and threaten humanity," they stressed.