BEIRUT, Lebanon — The town of Maarat al-Noaman in northern Syria was just last week the scene of a major victory for the insurgents, who drove government forces from checkpoints at a crucial crossroads on a major highway, apprehended scores of soldiers, celebrated atop captured armored vehicles and declared the town “liberated.”

On Thursday, jubilation turned to horror as government airstrikes sent fountains of dust and rubble skyward and crushed several dozen people who had returned to what they thought was a new haven in a country mired in civil war, according to reporters on the scene for a Western news agency, and antigovernment fighters and activists who backed up their accounts with videos posted online.

Men stumbled over rubble, carrying single bones nearly shorn of flesh and shredded body parts barely identifiable as human. Amid a swirling crowd of rescuers, two young men embraced and wept. A man in a baseball cap pointed out crumpled buildings that, he said, crushed women, children and elderly people sheltering there. An infant in a pink shirt lay motionless, then opened its eyes. “God is great,” said a rescuer, cradling the baby in his arms.

Maarat al-Noaman’s reversal of fortune highlights the dark turn that Syria’s civil war has taken in recent months, as fighting intensifies and the government and insurgents remain locked in an increasingly bloody stalemate, Syrian residents and military analysts said.