Italy avalanche rescuers race to find Rigopiano hotel survivors
Rescuers in Italy still hope to find survivors after an avalanche struck a mountain hotel, killing at least four people and leaving about 25 still missing in the snow.
Teams have been working at the scene for more than 24 hours.
The disaster struck the remote Rigopiano hotel, in the central Abruzzo region, after several earthquakes.
Rescuers have recovered three bodies. Two survivors, affected by hypothermia, have been sent to hospital.
Two people who were outside the hotel at the time of the avalanche survived. Children are among the missing.
The earthquakes, four of which were stronger than magnitude 5, terrified residents of rural areas who were already struggling with harsh conditions after heavy snowfall buried phone lines and took out power cables.
Prime Minister Paolo Gentiloni called for national unity, saying Italy was caught in an "unprecedented vice of frost and earthquakes".
European Commission President Jean-Claude Juncker said the rest of the EU stood ready to help because "an earthquake in Italy is an earthquake in Europe".
How difficult is the search?
Teams had to ski and shovel their way towards the site of the avalanche, reaching the hotel only at 04:30 (03:30 GMT) on Thursday.
Snow blocking an approach road held up a vast column of emergency vehicles.
"The upper part of the hotel it's not there anymore - it's full of snow inside the different rooms," said Dr Gianluca Fachetti, who was with the rescue teams.
"But there are several floors and we think most part of the people are on the first floor not the second or third, and it's very difficult but anyway we hope there could be someone still alive."
"There is always hope, if there were no hope the rescuers wouldn't give everything they've got," Fabrizio Curcio, head of Italy's civil protection department, was quoted as saying by Reuters news agency.
His teams, he said, would "continue to do everything possible during the night".
Paying tribute to the dedication of the rescuers, Prime Minister Gentiloni added: "I want to say that we are all holding our breath after what happened last night with the avalanche."
It appears the guests had gathered on the ground floor of the four-star spa hotel, close to the Gran Sasso mountain, to await evacuation following the earthquakes.
Twenty-two guests and seven staff members were registered as being at the hotel, among them children, but rescuers say the actual number could be 35.
The avalanche struck some time between 16:30 and 17:40, based on messages and calls sent by people at the hotel.
It partially brought down the roof and, according to some reports, shifted the building 10m (11 yards) off its foundations.
A guest who was outside the building at the time raised the alarm with his phone.
Giampiero Parete, whose wife and two children are missing, said he had gone to get something from his car: "I was covered by the snow but I managed to get out. The car was not submerged and I waited for the rescuers to arrive."
Mr Parete, who was taken to hospital with a fellow survivor, continued to make phone calls but it reportedly took until 20:00 before his pleas were acted on by the authorities.
Who are the missing?
A list of 23 names given by La Stampa newspaper suggests that most are Italians but they include a Swiss national and a Romanian.
Three are children aged six, seven and nine, and the oldest person on the list is a man of 60.
Seven of the missing are from the neighbouring region of Le Marche.
A couple from Le Marche who are not recorded in La Stampa's list, Marco Vagnarelli and Paola Tomassini, were last heard from at 16:30 on Wednesday, when Marco contacted his brother Fulvio on WhatsApp, Ansa reports. The avalanche had still not started at that point.
Marco had told his brother that their departure from the area was being delayed by the bad weather.
Analysis: Why so many quakes in Italy?
By Jonathan Amos, BBC science correspondent
The Apennines region saw three magnitude-6 tremors between August and October. A succession of quakes like this is often how the geology works.
The big picture is reasonably well understood. Wider tectonic forces in the Earth's crust have led to the Apennines being pulled apart at a rate of roughly 3mm per year - about a 10th of the speed at which your fingernails grow.
But this stress is then spread across a multitude of different faults that cut through the mountains. And this network is fiendishly complicated.
It does now look as though August's event broke two neighbouring faults, starting on one known as the Laga and then jumping across to one called the Vettore.
Then came October with a swathe of quakes that broke the rest of the Vetorre. But the stress, according to the seismologists, wasn't just sent north, it was loaded south as well - south of August's event.
And it's in this zone that we have now seen a series of quakes in recent days. About a dozen magnitude fours and fives.