Italy has been rocked by its most violent earthquake in 36 years, but nobody appears to have died.
Reports suggest around 20 people were injured, with nine having to be pulled from wreckage.
The huge 6.6 magnitude quake struck in central Italy this morning at around 7.40am (6.40am UK time).
The quake was centred near Norica - which dates back to around 1200 AD and has a population of around 5,000 - 68km (42 miles) southeast of Perugia.
It comes just week after tremors in the region killed more than 300 people.
The Basilica in Norica has been flattened - in one video nuns can be seen fleeing the scene before a clock tower which stood for hundreds of years collapsed.
“It was like a bomb went off,” the town’s deputy mayor, Pierluigi Altavilla, said. “We are starting to despair. There are too many quakes now, we can’t bear it any more.”
This earthquake was around 108 km (67m) deep - and reportedly felt as far away as Rome (130km away) and over the border in Croatia and Slovenia.
There are reports that cracks have appeared on St Paul's Basilica in the capital - forcing it to be closed to the public while the building is assessed.
The Metro underground train service in Rome also been closed while it is checked over.
In August, almost 300 people died when a 6.2 magnitude earthquake hit the area.
In the tourist town of Amatrice alone, 234 were killed. It, along with other towns and villages, suffered further significant damage yesterday.
Residents living in and around Norica, which is surrounded by dozens of towns, are reporting having been woken up by buildings shaking - and the sound of falling rocks.
Prime Minister Matteo Renzi promised a massive reconstruction effort.
He said: “Everything that needs to be done to rebuild these areas will be done.”
Pope Francis, in his Sunday blessing in the Vatican’s St Peter’s Square, said: “I’m praying for the injured and the families who have suffered the most damage, as well as for rescue and first-aid workers.”
Italian newspaper La Stampa reported that three people had been pulled alive from rubble in Tolentino - a town of around 20,000 people where several buildings have been said to have collapsed.
Emergency services are urging people to use SMS messages and WhatsApp to check on their friends and families - to avoid blocking emergency calls on mobile and phone landlines.
Marco Rinaldi, the mayor of Ussita - who was sleeping in his car after recent quakes, told ANSA news agency after the huge one this morning: “It’s a disaster, a disaster!
“I was sleeping in the car and I saw hell.”
Local TV crews are showing images of damage including rubble on the ground and to ancient structures around Norica.
In one video nuns can be seen being carried out from a church in Norica by firemen.
Also according to La Stampa, the head of civil protection, Fabrizio Curcio, has said at a press conference in the town of Rieti that “a dozen” people have been injured - mostly minor injuries but one serious.
The Monks of Norcia said the Basilica of St Benedict had been "flattened" in the quake.
They have posted an update to their website which reads:
"Dear friends,
"Around 7:40 AM, a powerful earthquake struck close to Norcia. The monks are all safe, but our hearts go immediately to those affected, and the priests of the monastery are searching for any who may need the Last Rites.
"The Basilica of St. Benedict, the historic church built atop the birthplace of St. Benedict, was flattened by this most recent quake. May this image serve to illustrate the power of this earthquake, and the urgency we monks feel to seek out those who need the Sacraments on this difficult day for Italy.
"Relying, as ever, on your prayers and support,
"Fr. Benedict."
The monks have since tweeted that people are trapped in the main square in Norica by buildings collapsing nearby.
Early indications are that the earthquake has mostly hit towns that have already been abandoned - especially in the wake of three large quakes in four days, people appear to have been on their guard.
The cliffside town of Arquata can be seen to have continued to crumble in the earthquake in pictures.
There are reports that the local hospital in Cascia, near Norcia, is being evacuated.
The mayor of Arquata del Tronto, Aleandro Petrucci, said: “It all came down, now there is no more town" - but he added that there were already “red zones” in place that had been abandoned after earlier quakes.
He said: “The few people who remained have gone out to the streets, and are embracing. Now we’re going around to see what happened."
The head of Civil Protection in Marche, Cesare Spuri, said: “There are collapses everywhere. We report collapses in Muccia, Tolentino and in the areas surrounding Macerata, we’re trying to establish if people are underneath the rubble. There was also a strong shock in Ancona.”
It is the 15th earthquake felt in central Italy in the last 71 hours.
The earthquake hit at 6.40am and was felt as far as Rome. Early reports had measured it as being between 6.4 and 7.1 in magnitude but were later on corrected with more accuracy.
This latest earthquake is the most powerful following a series of tremors that have hit the region.
It is also being reported as the largest in Italy since the 6.9 magnitude Irpinia earthquake of 1980.
Last quake a series of strong earthquakes hit Italy - shaking Rome's World heritage ancient buildings including the Colosseum and Pantheon.
Three quakes were felt, several hours apart, across a wide central area of the country.
The first tremor was a 5.4 on the Richter scale, the second 6.1 and the third 4.9, according to the United States Geological Society
Italy's National Commission for the Forecast and Prevention of Major Risks (CGR) cautioned Friday that more powerful earthquakes could hit the region in the nearest future, identifying at least three areas at risk for further seismic activity.
"There is no current evidence that the (seismic) sequence underway is coming to an end," the commission warned.
The earlier earthquakes struck near the border between the regions of Marche and Umbria, but the epicentre is still unclear.
They was also felt in Rome where local media reported some of Rome's ancient structures were shaken.
The tremors could be felt as far afield as Bologna.
The Mayor of the town of Ussita, Marco Rinaldi, said: "It was a very strong earthquake, apocalyptic.
"People are screaming on the street and now we are without lights.
"Many houses have collapsed. Our town is finished.'
Mr Rinaldi said: "The second quake was a long, terrible one."