Service members in South Korea who’ve attended New World Church in Daegu over the past 10 days must undergo a mandatory self-quarantine to monitor for symptoms of coronavirus, according to U.S. Forces Korea.

The move comes after South Korea reported 15 confirmed cases of the virus, now known as COVID19, stemming from the evangelical church Wednesday. That brings the total number of cases in South Korea up to 51, according to the South China Morning Post.

USFK commander commander Army Gen. Robert Abrams announced the quarantine on Wednesday, and said family members, civilians, and contractors also participate in the quarantine. The quarantine would last until the Centers for Disease Control and Prevention Korea conducts contact trace procedures to check who has had exposure to the virus, Abrams said.

“We must protect the force and our community by maintaining our “Fight Tonight” readiness.” Abrams said in a statement.

Additionally, Abrams said he is raising the risk assessment for USFK from low to moderate and that all troop’s non-essential travel to and from Daegu, where U.S. Army Garrison Daegu is located, will be cut off.

“All visitors who are not performing mission essential or official business will be denied access to USAG-Daegu and Area IV military installations for the next 24 hours, and this directive will be reassessed every 24 hours,” Abrams said.

Abrams also stressed that good hygiene the most effective way to halt the virus’ spread.

U.S. Army Garrison Daegu announced Wednesday non-mission essential personnel would not report to work on Thursday, and that the base’s high school, elementary school, and child development center would be closed that day.

× Fear of missing out? Sign up for the Early Bird Brief - a daily roundup of military and defense news stories from around the globe. Thanks for signing up. By giving us your email, you are opting in to the Early Bird Brief.

“Dual military families and single parents should speak to their chain of command and supervisors, but command teams will err on the side of the military families as to not cause undue burden and hardship,” U.S. Army Garrison Daegu said in a Facebook post.

Conditions will be assessed on a daily basis, according to the military installation.

USFK previously imposed a 14-day quarantine for all U.S. troops headed to South Korea after visiting China earlier this month. Family members and other DoD personnel were also strongly encouraged to participate in the quarantine following travel from China.

Hundreds of Americans have been evacuated from China and shuttled to various military installations to undergo quarantines. More than 300 evacuees who were transported to Travis Air Force Base and Marine Corps Air Station Miramar were released Tuesday after completing a 14-day quarantine.

The Centers for Disease Control and Prevention told National Public Radio that one person who was quarantined at Marine Corps Air Station Miramar tested positive for coronavirus and is continuing to receive medical treatment at a local hospital, but that the other evacuees have been “medically cleared.”

As of Feb. 18, there were more than 72,500 confirmed cases of coronavirus in China and more than 800 outside of China. Nearly 2,000 people within China have died, along with three outside of China.

There have been 15 confirmed cases in the United States, according to the World Health Organization.