South Korea deployed 900 military personnel after the Pyeongchang Organizing Committee (POCOG) quarantined the security guards. The POCOG said the guards suffered sudden outbreaks of diarrhea and vomited Sunday and were taken to the hospital, CNN reported. An investigation suggested the symptoms could have come from ground water being used in the food and beverages at the facilities, ESPN reported.
"The military personnel ... will be responsible for security checks of the 20 venues as they take up jobs such as security searches, previously done by civilian safety personnel, until the patients' condition is normalized," according to a statement from the POCOG.
All of the civilian guards are in stable condition, according to the statement.
Competitions at the Winter Olympics begin Feb. 8 and will continue through the closing ceremonies on Feb. 25.