A magnitude 6.2 earthquake has struck central Italy, leaving at least 38 people dead and 150 missing, as rescuers search for survivors.
Many of the dead were in Accumoli, close to the epicentre, and a short distance away in Amatrice, which was largely reduced to rubble.
The village of Pescara del Tronto was levelled to the ground and the number of dead was expected to rise.
The quake hit at 03:36 (01:36 GMT), 100km (65 miles) north-east of Rome.
Prime Minister Matteo Renzi paid tribute to the volunteers and civil defence officials who had rushed to the scene in the middle of the night and used their bare hands to dig for survivors,
The quake struck at a shallow depth of 10km and its intensity was compared to that of the Aquila earthquake in April 2009 in which 309 people died.
Some buildings in the capital shook for 20 seconds as the quake struck the regional border area of Umbria, Lazio and Le Marche. It was felt from Bologna in the north to Naples in the south. Some 80 aftershocks have been reported since.
Local authorities were unsure of the full extent of casualties but 28 deaths were reported in Accumoli and Amatrice.
At least 11 people were reported dead including children in the neighbouring villages of Arquata del Tronto and Pescara del Tronto. Hundreds of people were injured across the region, officials said.
The mayor of Arquata del Tronto, Aleandro Petrucci, spoke of a disaster. “The village isn’t there any more. Almost all the houses in Pescara del Tronto have collapsed.”
An elderly couple and a boy were among the victims there while 20 people have been taken to hospital. Two boys aged four and seven were pulled alive from the rubble of the house they had been staying in with their grandmother, Ansa news agency reports. Rescuers said they had been sheltering under a bed.
Rescuers were still trying to reach the remote village of Peracchia di Acqua Santa Terme a few kilometres to the east.
Some of the worst damage was in the town of Amatrice, where rescue efforts were under way to find survivors. At least 17 people in the town died and several more were missing, including three nuns.
“The roads in and out of town are cut off,” said mayor Sergio Pirozzi. “Half the town is gone. There are people under the rubble. There’s been a landslide and a bridge might collapse.
“There are tens of victims, so many under the rubble. We’re preparing a place for the bodies.”
Residents described using sheets to climb down from the upper floors of damaged houses. The local hospital was described as unusable and survivors were taken to nearby towns for treatment.
The town’s 13th Century bell-tower was one of the few historic buildings in the centre that remained standing. Amatrice is popular with holidaymakers from Rome and renowned as the home of amatriciana pasta sauce.
The main street through the town has been devastated and emergency workers are trying to reach six people in a collapsed building.
The BBC’s James Reynolds, who is in Amatrice, said that sniffer dogs were being sent into buildings to search for more survivors and local authorities were trying to assess the number of people missing.
In Accumoli, a short distance to the north of Amatrice, four people were confirmed dead and eight more were missing.
“There is a family of four under a collapsed house and sadly there are two small children among them,” said Mayor Stefano Petrucci.
A local photographer spoke of 15 rescuers digging with their bare hands to try to reach the family.
“They can hear the screams of the mum and one of the children,” he said.
Rescuers were also trying to dig out a 58-year-old man who was trapped in his home.
Accumoli is popular with holidaymakers and most of the 2,500 people left displaced by the earthquake were said to be visitors.
Italian President Sergio Mattarella described the disaster as “a moment of grief and of appeal to shared responsibility”.
Mr Renzi promised affected areas that “no family, no city, no hamlet will be left alone”.
Why is Italy at risk of earthquakes? By Jonathan Amos
Quakes are an ever-present danger for those who live along the Apennine mountain range in Italy.
Through the centuries thousands have died as a result of tremors equal to, or not much bigger than, the event that struck in the early hours of Wednesday. The modern response, thankfully, has been more robust building and better preparation.
Mediterranean seismicity is driven by the great collision between the African and Eurasian tectonic plates; but when it comes down to the specifics of this latest quake, the details are far more complicated.
The Tyrrhenian Basin, or Sea, which lies to the west of Italy, between the mainland and Sardinia/Corsica, is slowly opening up.
Scientists say this is contributing to extension, or “pull-apart”, along the Apennines. This stress is compounded by movement in the east, in the Adriatic.
The result is a major fault system that runs the length of the mountain range with a series of smaller faults that fan off to the sides. The foundations of cities like Perugia and L’Aquila stand on top of it all.
Seismologist Andrea Tertulliani said there were sure to be further, numerous shocks that would probably diminish in intensity.
“But it can’t be ruled out that there could be another shock on the same scale as the main one,” he added.
Italy’s Civil Protection agency described the earthquake as “severe”.
“It was so strong,” Lina Mercantini of Ceselli, Umbria, told Reuters. “It seemed the bed was walking across the room by itself with us on it.”