"In difficult times Italy knows what to do when things go wrong," the PM says, promising that no Italian who needs help because of the quake will be left unaided. Mr Renzi's staff say that he has cancelled all appointments in the aftermath of the quake.

The Italian Prime Minister, Matteo Renzi, says he is going to the affected area this afternoon. 

He has praised the generosity of the volunteers and all those who started working in the middle of the night:

"I would like to thank everyone on the part of the government, those who have dug with their bare hands, those who have dealt with communications, I would like to thank all those who have shown how important voluntary work and civil protection is....We must be equipped for the emergency of the next few hours, days and weeks."

The US Geological Survey predicts widespread damage and heavy economic losses, requiring national or international level response.

Image source, USGS

The Italian president, Sergio Mattarella, has issued a statement, saying: 

"This is a moment of grief and of appeal to shared responsibility. The whole country should pull together in solidarity with the population affected. 

"My first thoughts go to the many victims of this devastating earthquake, which has affected such a large part of the country.

"I want to thank the local authorities, Civil Protection, the fire service, the police, armed forces, and volunteers for their efforts and dedication in the rescue work.

"In the immediate term we need to put all our efforts into saving human lives, looking after the injured and ensuring the best conditions for the displaced.

"After that, we need a joint and speedy effort to guarantee the reconstruction of the places that have been destroyed, getting businesses going again, and getting back to normal life."

"At the moment there's hundreds of rescuers trying to save those who are still alive under the rubble," photographer Emiliano Grillotti tells the BBC. "Amatrice is totally in ruins. One of the most beautiful villages in the whole of Italy now doesn't exist. Everything is rubble, only rubble."

Forestry police quoted by the AP news agency say they have extracted dozens of people alive from the rubble in the hard-hit town of Pescara del Tronto in Le Marche region. But AP says rescue crews still haven't reached the nearby hamlet of Peracchia di Acqua Santa Terme.    

Thirty-seven people are dead and 150 missing, officials say.

Today Programme
BBC Radio 4

Sabrina Sbermola, an Italian tour guide who is about 10km from the epicentre of the earthquake, tells Nick Robinson she is worried about her aunt and her cousin.  

Appeals for blood donors have been made to anyone in the Rome area or the quake area - they can do so in the nearest hospital or AVIS centre (Italian Association of Blood Donors)

2009 - 6.3 magnitude quake hits central city of L'Aquila, killing more than 300 people.

2002 - Quake in Molise, southern Italy, trapped 50 children in layers of concrete, 27 of them killed.

1980 - 6.9-magnitude quake killed nearly 3,000 people and left more than 200,000 homeless. 

1908 - Most deadly earthquake of 20th century in southern regions of Reggio, Calabria, and Sicily, killing an estimated 80,000 people.