The gymnasium-auditorium facility at a resort in Gyeongju collapsed Monday while 565 incoming students from Busan University of Foreign Studies were at the resort for a welcome party that was part of a new student orientation program, South Korea's Yonhap News Agency reported.
"Ten people are confirmed dead, two were seriously injured and 101 others sustained minor injuries," a Security and Public Administration Ministry official told reporters in Seoul.
Nine of the dead were university students and the 10th was a party organizer, police said.
Eleven other party organizers remained unaccounted for, though officers said it was unlikely they were trapped in the rubble.
"A rescue operation is still under way, just in case," the ministry official said.
Heavy snow on the roof could have caused the collapse, but officials also were investigating whether the building was an unauthorized structure that didn't meet safety standards.