The death toll from a powerful earthquake that shook central Italy rose to 247 on Thursday, officials said, as rescuers desperately searched for survivors in the rubble of devastated mountain villages. Hundreds of others were injured, some critically, and an unknown number were trapped under the ruins of collapsed buildings after Wednesday's pre-dawn quake. Amid scenes of carnage, dozens of emergency services staff and volunteers were preparing to work through the night in the hope of rescuing more survivors from the ruins. Rescuers had pledged to work through the night in the hope of finding people alive in the mangled wreckage of homes. Prime Minister Matteo Renzi had earlier said at least 120 people were killed in the earthquake. "This is not a final toll," he had warned after visiting the badly hit village of Amatrice.

Hundreds of people were to spend a chilly night in hastily assembled tents with the risk of aftershocks making it too risky for them to return home.

Scores of buildings were reduced to dusty piles of masonry in communities close to the epicentre of the quake, which had a magnitude of between 6.0 and 6.2.

It hit a remote area straddling Umbria, Marche and Lazio at a time of year when second-home owners and other visitors swell the numbers staying there. Many of the victims were from Rome. The devastated area is just north of L'Aquila, the city where some 300 people died in another quake in 2009.

Most of the deaths occurred in and around the villages of Amatrice, Accumoli and Arquata del Tronto.

Guido Bordo, 69, lost his sister and her husband after they were trapped inside their holiday house in the hamlet of Illica, near Accumoli.

"There's no sound from them, we only heard their cats," he told AFP before the deaths were confirmed.

"I wasn't here. As soon as the quake happened, I rushed here. They managed to pull my sister's children out, they're in hospital now," he added, wringing his hands in anguish.

Among the victims was a nine-month-old baby girl whose parents survived, an 18-month-old toddler and two other young children who died with their parents in Accumoli.

Two boys aged four and seven were saved by their quick-thinking grandmother, who ushered them under a bed as soon as the shaking began, according to reports. She also survived but lost her husband.