One principal and three vice principals at elementary schools in Gangwon Province tested positive for COVID-19 on Thursday, prompting the closure of dozens of schools in the region. 

According to the Gangwon Provincial Office of Education, the four educators are from elementary schools in Wonju, Hwacheon and Hongcheon. 

The four reportedly teamed up for a recent teachers' training session or visited the same school. They are said to have come into contact with a number of teachers before testing positive for the virus. 

The education office decided to temporarily close 20 elementary schools and four middle schools in the region Friday, which will switch to online classes. The affected elementary schools account for five-point-three percent of the 376 elementary schools in the province.