Rescue crews digging through an Italian hotel buried in an avalanche say there could be additional survivors more than three days after tonnes of snow came barrelling down a mountainside.

Rescuers told reporters in the central Apennine mountains on Sunday morning there were air pockets in some of the Hotel Rigopiano’s wreckage. But they have been unable to reach all those areas.

Nine survivors, including four children, from the avalanche last Wednesday were located in air pockets inside the crushed hotel on Friday. Rescue officials say there are other spaces where some of the 23 people still missing might be found alive.

Buoyed by the rescues on Friday, search crews have fought against the clock and deteriorating weather conditions including fresh snowfall, rain and freezing temperatures. Officials say the risk of fresh avalanches is high.

Doctors at a hospital in Pescara said one of the adult survivors was in a fair condition after undergoing surgery for a crushed arm, but that all of the other patients were doing well. The children were being moved from intensive care to the paediatric ward.

Dozens of friends and family members kept vigil at the hospital, some growing frustrated at the lack of news.

The search has included sending sound-sensitive instruments down into snow-crusted debris. Rescuers passed crates full ofhardened snow and ice to colleagues as they tried to penetrate deeper into the wreckage, creating the equivalent of elevator shafts to allow searchers to descend into the smashed hotel.

Searchers also used devices that could pick up any electronic waves emitted by cell phones of the missing, said Walter Milan, a spokesman for the alpine rescuers.

That voices have not been heard lately does not mean no one is still alive, he said, explaining “we know that thick walls and snow isolates” possible voices.

The avalanche dumped five metres of snow on top of the resort, 115 miles north-east of Rome. The region, which has been blanketed by heavy snowfall, was also rocked by four strong earthquakes on Wednesday, though it was not clear if they set off the avalanches.