Rescuers have removed two bodies from a hotel engulfed by an avalanche in central Italy as a desperate search for up to 35 other people continues.
Heavy snow and disruption caused by multiple earthquakes have hindered rescue efforts in the rubble of the Rigopiano hotel, in the Abruzzo region.
Rescuers say they have heard nothing in the rubble while sniffer dogs are reportedly unable to locate victims.
Two people who were outside the hotel at the time of the avalanche survived.
Four earthquakes above magnitude five rocked central Italy on Wednesday, with tremors continuing into the night.
The quakes compounded problems resulting from snow and freezing weather, with power lines brought down and villages temporarily cut off.
Rescue operations are under way across central Italy and European Commission President Jean-Claude Juncker has said the EU is ready to help.
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 (15:30 GMT) and 17:40 on Wednesday, when the first known appeal for help was made.
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."
A couple was quoted as telling rescuers in a message: "Help, we're dying of cold."
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 Marche.
A couple from 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.
Why is the rescue work so difficult?
Video shows hotel interiors choked with walls of debris and snow.
"The hotel is almost completely destroyed," Antonio Crocetta, a member of the Alpine rescue squad who was at the scene, told Reuters news agency by phone.
"We've called out but we've heard no replies, no voices. We're digging and looking for people."
The first rescuers only reached the hotel on skis at 04:30 on Thursday morning. A line of rescue vehicles snaked along an approach road as they waited for it to be cleared.
Earlier on Thursday, Italian media said three bodies had been extracted while, according to an unconfirmed report, a fourth body had been found inside but not yet recovered.
But the fire service said only two bodies had been retrieved.
How widespread is the damage from the quakes?
The tremors caused chaos across central Italy, compounding problems caused by heavy snow and freezing weather.
Rescue services initially struggled to reach rural communities in regions like Marche.
One man was killed by a falling roof in Marche and another person swept away by a landslide in Abruzzo.
People have been evacuated from their homes in some areas.
An earthquake rocked central Italy on 24 August, killing 298 people die. Another quake in October killed no-one, as most of the population centres had been evacuated.
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.
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