Hopes of finding survivors dwindled on Thursday more than 24 hours after an avalanche struck a luxury mountain hotel in Italy, burying up to 30 people under tonnes of snow and debris.

The Civil Protection department said just two bodies had been recovered but its chief said the search for victims and possible survivors would continue through the night. Earlier in the day, Italian authorities had said three bodies were found.

"There is always hope, if there were no hope the rescuers wouldn't give everything they've got," Fabrizio Curcio told reporters.

He said his teams would "continue to do everything possible during the night," even though conditions were far more difficult than in daytime.

1st images from inside hotel show devastating impact of avalanche 1:12

More quakes possible

The disaster struck hours after four earthquakes with a magnitude above 5 hit central Italy. Titti Postiglione, head of the department's emergency office, said more snow could fall from peaks in the Gran Sasso mountain range in the central Abruzzo region because the temperature was rising, while further quakes were possible.

"This is an enormously complex rescue operation," she said.

So far, only two survivors have been found after a powerful avalanche hit a four-star hotel. (Andreas Solaro/AFP/Getty Images)

The gabled peaks of parts of the roof and a row of windows were the only sections of the four-storey Hotel Rigopiano visible after the wall of snow smashed into the four-star spa resort on Wednesday evening.

"This is a tragedy of enormous proportions," said Health Minister Beatrice Lorenzin.

2 survivors found

Local authorities said about 30 people had been in the building at the time, including two children. The only survivors found were two men who had been outside when the disaster struck.

"The hotel is almost completely destroyed. We've called out but we've heard no replies, no voices," said Antonio Crocetta, a member of the Alpine Rescue squad. "We're digging and looking for people," he told Reuters by phone from the isolated location.

The hotel is almost completely destroyed. We've called out but we've heard no replies, no voices. - Antonio Crocetta, Alpine Rescue

Rescue workers entered what appeared to be a lobby decorated with oil paintings and plants, where a landslide had torn through a wall, television footage showed.

Mattresses and furniture were spotted dozens of metres away and sniffer dogs were helping with the search.

A photo taken from a video shows a survivor, helped by rescuers, coming out from Hotel Rigopiano in Farindola. Some 30 people are still missing. (Guardia Di Finanza via Reuters)

Close calls

"I am alive because I went to get something from my car," Giampiero Parete told medical staff.

Italian media said he had been on holiday with his wife and two children, who are missing.

Prime Minister Paolo Gentiloni called for national unity, saying Italy was caught in an "unprecedented vice" of earthquakes and heavy snows.

Up to 30 people believed to be in hotel when snow hit 0:33

The rescue operation was hampered by deep snow that has fallen on the Gran Sasso in recent days. Drifts made snow as deep as five metres in some places and snow plows struggled to cut a path up winding mountain roads.

The first rescuers arrived at 4.30 a.m. local time after having to ski through a blizzard to reach the site. After dawn broke, emergency services sent in helicopters.

A base camp for rescue workers was set up in the town of Penne, some 10 km away, where ambulances waited.

The avalanche shunted the 43-room hotel, which is 1,200 metres above sea level, about 10 metres down the hill, according to media reports. Italian media said guests at the hotel had checked out and were waiting for a snow plow to arrive to open up the road and let them down the mountain when the avalanche struck.