At least 33 American service members stationed at Osan Air Base tested positive for the coronavirus, officials said Friday, after the base came under fire for a no-mask dance party in disregard of social distancing rules.

The infections were reported on Thursday and Friday at the base, some 70 kilometers south of Seoul, and contact tracing is under way, according to South Korean government officials.

A dance party took place at the base Saturday involving dozens of individuals not wearing face masks.

The incident has drawn criticism, as South Korea is experiencing the fourth wave of COVID-19 and the country has enforced the highest level of social distancing for the greater Seoul area since mid-July.

At that time, South Korea and the United States were also conducting the major combined exercise while enforcing strict antivirus rules. The nine-day exercise was concluded Thursday.

"We've been conducting virus tests on about 800 South Korean service members as a preventive step," a defense ministry official said, adding that no virus cases have been reported among them so far.

"We are aware of a recent cluster of confirmed COVID-19 at Osan Air Base and are continuing to gather the facts and information surrounding these positive cases," USFK said in a release sent to Yonhap News Agency.

"As a matter of policy, USFK does not publicly discuss specific details about confirmed cases but maintains an open and transparent posture with our USFK and ROK communities by announcing confirmed cases through a variety of platforms on a routine basis," it added.

ROK is the acronym of South Korea's official name, the Republic of Korea.

The US military has yet to officially announce detailed information on those cases. The USFK last released official data on COVID-19 cases Tuesday, and the total caseload among its population came to 1,286. (Yonhap)