South Korea confirmed two COVID-19 cases at a school on Tuesday, the first instance of a spread of the virus at a school since the facilities reopened for offline classes. 

According to Daejeon City on Tuesday, two elementary students tested positive for the coronavirus that day. 

The students, the 120th and 121st cases in Daejeon, reportedly contracted the virus after coming into contact with the city's 115th case, a fifth grader at the school who tested positive the previous day.

The 115th patient is reportedly a classmate of the 120th case and went to the same gym with the 121st case, who is also a fifth grader. 

Health authorities decided to test all fifth graders at the school. The number of related infections may rise further as tests are underway for about 160 students and people who used the gym.