The fire department official said it was too soon to comment on how many people were injured in total.
Two South Koreans died and several others, including athletes attending world aquatic championships, were injured when a structure collapsed in a nightclub in the city of Gwangju early on Saturday, a fire department official said.
The two died when a two-level structure in the club collapsed around 2 a.m. KST (1700 GMT Friday), pinning and hitting revelers, the official said.
Yonhap news agency reported that nine athletes competing in the 2019 FINA aquatic World Championships were injured, though none of them seriously.
They included four from the United States, two from New Zealand, and one each from the Netherlands, Italy and Brazil, Yonhap said, citing city and fire department officials.
Their injuries ranged from bruising to lacerations on their hands or feet, the agency said.
The fire department official confirmed some of the athletes had been hurt but said it was too soon to comment on how many people were injured in total.
A spokesman for Gwangju city could not be immediately reached.