Rescuers pulled four people alive from an avalanche-hit Italian hotel on Saturday and clung on to hopes of saving some of the 23 people still missing three days after the disaster struck.

Saturday's rescues lifted the total number of survivors to 11. But with no new signs of life detected, any possible survivors still trapped under the snow-covered rubble were facing a fourth night in the freezing mountains of central Italy.

Teams of mountain rescuers and firefighters had been boosted by Friday's dramatic rescue of all four children who were inside the Hotel Rigopiano, along with the mother of two of them.

Two men and two women were then pulled out alive in the early hours of Saturday.

But optimism faded over the course of a day in which emergency personnel had to battle atrocious conditions at 1,200-metres (3,900 feet) above sea level.

Enrica Centi, a spokeswoman for the mountain rescue teams involved in the operation, said heavy snow and poor visibility which grounded helicopters was hampering the effort.

"Those on site say they have heard signs of possible life but it may just have been bits of rubble collapsing, it's impossible to tell," she said.

- 'Easily still alive' -

Returning from an exhausting shift at the hotel, mountain rescuer Alessandro Massa, 34, was defiantly upbeat.

"I haven't slept for three days, but we're keeping positive, we are going to get the people home," he said.

"We've been shifting snow and rubble by hand, working mainly in the areas where the survivors rescued so far have been found.

"We're using electric saws to cut through the wreckage but it's dangerous so progress is slow.

"There are still puffs of vapour from parts of the wreckage, so there are still air pockets, and that makes us think there's still hope. Those still trapped underneath could easily still be alive."

Among the missing was hotel kitchen staffer Luana Biferi. "Our hope is that she may have been in the kitchen when the avalanche hit because it has a thick external wall which may have protected her," her neighbour Antonio Lobolo, 42, told AFP.

"Our whole village is waiting anxiously for news."

Teams of firefighters and police are combing a debris-strewn area bigger than several football pitches as a result of the devastating force of the avalanche, which dragged the three-story hotel some 10 metres (30 feet) from its foundations.

They were using scanning equipment to try to pick up signs of mobile phones amid an ever-present risk of further masonry collapses or fresh snow slides.

Centi, the spokeswoman of the rescue service, said: "There is still hope of finding more people alive even if we don't hear their voices because there could be people trapped behind a concrete wall which prevents us from hearing them."

- Psychologically exhausted -

Among the survivors were two men who were outside the hotel when the avalanche struck just before nightfall on Wednesday. Five bodies had been recovered by dusk on Saturday.

In a first official update on the numbers at the hotel when the avalanche hit, the prefecture in the nearest city, Pescara, said 23 people remained unaccounted for.

The children survived because they were in a games room which did not cave in, Edoardo Di Carlo, aged 9, told journalists.

Edoardo's mother was confirmed late Saturday as one of the five people to have died. His father was among the missing, along with the parents of Samuel Di Michelangelo, 7.

"They are physically fine, they suffered only mild hypothermia but psychologically they have been through an ordeal," said Tullio Spino, a doctor at the Pescar hospital where the boys were recovering.

The other two children were from the same family of four, all of whom survived.

The rescuers were joined by a group of asylum-seeking migrants from Senegal and Guinea, said Red Cross spokesman Ensa D'Alessandro.

"The boys will be working in the tent in shifts, giving a hand to the cook and helping out wherever needed. Two of the group are already up there," he said.

The avalanche followed four earthquakes of more than five magnitude in the space of four hours earlier on Wednesday.

The death toll from the quake, not including the avalanche victims, rose to five on Saturday.

Some 33,000 homes were still without power and more than 8,000 troops and emergency services were deployed in the relief effort.

Around 120 residents of Valle Castellane were being helicoptered out of their snow-bound village.