A powerful 6.2-magnitude earthquake devastated mountain villages in central Italy on Wednesday, leaving at least 18 people dead and dozens more injured or unaccounted for.

Scores of buildings were reduced to dusty piles of masonry in communities close to the epicentre of the pre-dawn quake in a remote area straddling the regions of Umbria, Marche and Lazio.

Deaths were reported in the villages of Amatrice, Accumoli and Arquata del Tronto as residents and emergency services battled frantically to rescue people trapped beneath the ruins after the quake hit as people slept.

It was Italy's most powerful earthquake since 2009, when about 300 people died in and around the city of Aquila, just to the south of the area hit on Wednesday.

Prime Minister Matteo Renzi cancelled a planned trip to France for a meeting with European Socialist leaders and other engagements to oversee the response to the disaster.

"The situation is dramatic, there are many dead," said Amatrice mayor Sergio Pirozzi. "Half the village has disappeared."

Pope Francis interrupted his weekly audience in St Peter's square to express his shock at the news.

"To hear the mayor of Amatrice say his village no longer exists and knowing that there are children among the victims, is very upsetting for me," he said.

- 'Completely disintegrated' -

Fabrizio Curcio, the head of Italy's civil protection service, classed the quake as "severe". The shocks were strong enough to wake residents of central Rome, some 150 kilometres (90 miles) away.

The worst damage was suffered by Pescara del Tronto, a hamlet near Arquata in the Marche region which civil protection workers described as having been virtually razed.

Ten bodies had been recovered there by mid-morning and rescuers were braced for further fatalities.

Aleandro Petrucci, the mayor of Arquata, said Pescara had "just completely disintegrated."

Another two people died and a family of four including two young children were trapped, feared dead, in their collapsed house in Accumoli, according to its mayor Stefano Petrucci.

"We have a tragedy here," said Petrucci. "There are people under the ruins, it is not a good situation."

- Gastronomic beauty spot -

A village resident told Rai television that she had been woken by the shaking in time to witness the wall of her bedroom cracking open. She was able to escape into the street with her children.

In Amatrice, the president of the Lazio region confirmed six bodies had been recovered.

The village was packed with visitors at the peak of the summer season when the quake struck, destroying the picturesque hilltop village's main street.

The mayor said difficult access to the village had prevented emergency services getting through.

"There is a landslide on one road, a bridge is about to collapse on the other one," he said. "We can hear voices under the rubble."

Amatrice is famous in Italy as a beauty spot and is a popular holiday destination for Romans seeking cool mountain air at the height of the summer.

The first quake struck shortly after 3.30 am (0130 GMT), according to the United States Geological Survey, and a 5.4-magnitude aftershock followed an hour later.

USGS's PAGER system, which predicts the impact of earthquakes, issued a red alert -- suggesting significant casualties and damage based on previous quake data.

In 2009, a 6.3-magnitude earthquake struck close to the university city of Aquila in the Abruzzo region and left more than 300 people dead.

That disaster led to lengthy recriminations over lax building controls and the failure of authorities to warn residents that a quake could be imminent.

Italy is often shaken by earthquakes, usually centred on the mountainous spine of the boot-shaped country.

Another quake hit the northern Emilia Romagna region in May 2012, when two violent shocks 10 days apart left 23 people dead and 14,000 others homeless.