At least six people are believed to have died after a powerful earthquake struck central Italy, destroying dozens of villages, according to local media reports.
The first confirmed victims of Wednesday's earthquake were an elderly couple whose home collapsed at Pescara del Tronto in the Marche region to the east of the epicentre, national broadcaster Rai and other media outlets reported.
Another person died and a family of four, including two young children, were trapped, feared dead, in their collapsed house in Accumoli, close to the epicentre, the village mayor said.
The US Geological Survey said it was a 6.2 magnitude quake that hit near the town of Norcia, in the region of Umbria, at 3.36am local time (01:36 GMT).
The earthquake caused buildings to collapse and sent panicked residents fleeing into the streets of numerous towns and cities.
The mayor of the small town of Amatrice reported extensive damage.
"Half the town is gone," Sergio Pirozzi told RAI state television. "There are people under the rubble. ...There's been a landslide and a bridge might collapse."
Italy's civil protection agency said the earthquake was "severe".
A 5.5 magnitude aftershock hit the same region an hour after the initial quake.
Luca Cari, fire department spokesman, said "there have been reports of victims" in the quake zone, but he did not have any precise details.
Besides Amatrice, the worst hit towns were believed to be Accumoli, Posta and Arquata del Tronto, Cari told Reuters news agency, adding that helicopters would be sent up at first light to assess the damage.
'It was so strong'
"It was so strong. It seemed the bed was walking across the room by itself with us on it," Lina Mercantini of Ceselli, Umbria, told Reuters.
Olga Urbani, in the nearby town of Scheggino, said: "Dear God! It was awful. The walls creaked and all the books fell off the shelves."
Residents of Rome, about 170km from the registered epicentre, were woken by the quake, which rattled furniture and swayed lights in most of central Italy.
A hostel on the Gran Sasso mountain, a popular area for hikers and climbers, said on its Facebook page that a large piece of rock had collapsed as a result of the tremor.
The spokesperson for Matteo Renzi, Italy's prime minister, said on Twitter the government was in touch with the country's civil protection agency and following the situation closely.
The last major earthquake to hit Italy struck the central city of L'Aquila in 2009, killing more than 300 people.