As many as 450 students were believed to have been attending a concert in the building when the roof caved in around 9:15 pm (1215 GMT).

 Rescue workers carry a victim, medical condition unknown, from a collapsed resort building in Gyeongju, South Korea, Monday, Feb. 17, 2014. Photo by AP

Police officials quoted by the Yonhap news agency said ten people had been confirmed killed in the collapse and at least a dozen were thought to still be trapped inside the building, down from around 50 earlier in the evening.

Nine of the dead were college students whilst the tenth fatality was believed to be a party organiser, police said, adding that three students and 11 party organisers remained unaccounted for.

A spokesman for the local fire service had earlier told AFP by telephone that 73 people were injured, 15 of them seriously.

Rescue workers were continuing to search for any students who were feared trapped inside the collapsed structure, he said.

Yonhap reported that police feared the toll could rise throughout the night, with around 400 rescuers on the scene.

The collapse appeared to have been caused by heavy snow which had piled up on the roof of the auditorium.

- Shouting and screaming -

"The ceiling came crashing down at the front near the stage," one student told the YTN news channel.

"Then pandemonium broke out and everyone started rushing towards the exits, shouting and screaming," he added.

Footage broadcast on YTN showed fire officials using torchlights to search for people inside the building, its roof a mass of twisted metal.

Pictures from the Yonhap news agency showed injured students being carried away on stretchers from the largely metallic structure that appeared to have buckled in on itself.

In one shot, a young woman could be seen trapped under debris as helmeted rescue officials tried to free her from the twisted wreckage of the building.

The ground around the building was covered with a thick blanket of snow.

"Heavy equipment has been brought in to clear the debris," the fire official said.

The auditorium was part of the Mauna Ocean Resort, which had been hosting a freshman orientation event for close to 1,000 students from a foreign language college in the southern city of Busan.

The resort was in an area that has experienced exceptionally heavy snowfall, with more than 50 centimetres (20 inches) falling in the last week.

Fire officials told Yonhap that they had difficulty reaching the resort which is high up a mountain, adding that fresh snow was falling on Monday night.

The news agency said police officials would open an investigation once the rescue work had been completed.

According to Yonhap, investigators will focus on whether snow had been cleared from the roof of the auditorium and whether the building was an unauthorised structure that had failed to meet safety standards.

The city of Gyeongju is a popular tourism spot for both Korean and international travellers. Once the capital of the Silla kingdom, it boasts numerous historical sites and is located at the southern fringe of the Taebaek mountains.

The website for the Mauna Ocean Resort shows a sprawling holiday complex nestled on a mountainside complete with holiday villas and a golf course.