At least 90 people are believed dead and tens of thousands homeless after an earthquake hit L'Aquila and other towns in central Italy, rescuers say.
About 1,500 people were injured and many people are still missing as rescuers search desperately for survivors trapped beneath rubble.
The 6.3-magnitude quake struck at 0330 (0130 GMT) close to L'Aquila.
Prime Minister Silvio Berlusconi, who is in the city, has promised a "record number of rescuers".
"Nobody has been left on their own," he said, adding that a field hospital was being set up to help local medical services. Earlier, he declared a state of emergency.
Altogether, 26 cities and towns have been damaged, officials say. In L'Aquila, 95km (60 miles) north-east of Rome, between 3,000 and 10,000 buildings in the medieval city may have been damaged.
Between 30,000 and 40,000 people are believed to have lost their homes and the authorities are working to find them shelter before nightfall.
The BBC's Duncan Kennedy in L'Aquila described bemused and confused locals wrapped in blankets and carrying their personal belongings in suitcases walking, like a stream of refugees, through the devastation.
The rescue service is stretched to breaking point as it tries to reach all the devastated buildings and deal with the mounting casualty toll, our correspondent adds.
State of emergency
Earlier, the mayor of L'Aquila, Massimo Cialente, said some 100,000 people had left their homes.
Latest from Duncan Kennedy, L'Aquila
Here in the centre of the city, building after building has been left destroyed or half standing with cracks and holes.
We watched as rescue workers struggled to pull out survivors, crawling on their stomachs to try to reach those trapped inside.
There is a stream of almost ghostly figures, local people caught up in the early hours this morning in this earthquake, who are pouring past us wearing blankets.
They are pulling suitcases and luggage past this collapsed building trying to get to safety. People are wandering around in a dazed state.
A university dormitory, churches and a bell tower are believed to be among the buildings that had collapsed.
Many residents and rescuers used their bare hands to clear the debris from collapsed buildings, although the army and civil protection units from around Italy are joining the effort.
Survivors, some still in their night clothes, hugged each other as they waited for news of friends and relatives.
Hundreds waited at the city's main hospital, where doctors were forced to treat people in the open air because only one operating room was functioning.
Francesco Rocca of the Italian Red Cross said two field hospitals were arriving from Rome, but warned of the difficulties ahead.
"The biggest problem will arrive in the night because there are thousands and thousands of people that we have to host in tents, in the hotels," he told the BBC.
Deaths were reported in the surrounding towns and villages of Castelnuovo, Poggio Picenze, Tormintarte, Fossa, Totani and Villa Sant'Angelo.
But it is feared the toll could rise further as rescuers try to reach the many outlying villages and homes in the quake zone.
Phone and power lines remain down, and some bridges and roads have been closed as a precaution as the region was hit by a series of aftershocks.
Panic
The earthquake happened hours after a 4.6-magnitude tremor shook the area but caused no reported damage.
L'AQUILA
Medieval city, founded in the 13th Century
Capital of the mountainous Abruzzo region
Population 70,000, with many thousands more tourists and foreign students
Walled city with narrow streets, lined by Baroque and Renaissance buildings
Thousands of the city's 70,000 residents ran into the streets in panic following the 30-second tremor.
Survivors described finding themselves looking out on to open streets as the walls of their buildings fell away.
A student dormitory was said to be one of the buildings badly damaged. Rescuers were reportedly searching the rubble for people feared trapped inside.
"We managed to come down with other students but we had to sneak through a hole in the stairs as the whole floor came down," student Luigi Alfonsi, 22, said.
"I was in bed - it was like it would never end as I heard pieces of the building collapse around me."
MAJOR ITALIAN QUAKES
2002
- 30 die, including 27 pupils and their teacher, in the southern town of San Giuliano di Puglia
1997
- 13 die and priceless cultural heritage lost in the central Umbria region
1980
- Nearly 3,000 people die, some 9,000 injured and 30,000 displaced near Naples
Correspondents say that L'Aquila, capital of the mountainous Abruzzo region, has many old buildings not built to withstand a strong earthquake.
Even some modern structures on the outskirts of the city were reported to have collapsed.
The earthquake was also felt in Rome.
Italy lies on two fault lines and has been hit by powerful earthquakes in the past, mainly in the south of the country.
One-Minute World News
E-mail this to a friend
Printable version
'Lucky' UK survivor describes quake
Bookmark with:
What are these?