(CNN) South Korea has deployed 900 military personnel after 1,200 security guards were pulled from duty following an norovirus outbreak at Winter Olympic facilities in Pyeongchang.

Organizers said 41 security guards had suffered a sudden onset of vomiting and diarrhea on Sunday and had been taken to hospital. The outbreak comes just days before the opening of South Korea's 2018 Winter Olympics on Thursday.

To prevent the spread of the disease, the other guards were withdrawn and replaced with 900 military personnel as of Monday afternoon, a statement from the Pyeongchang Olympics committee said.

"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," the statement said.

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All the civilian guards were in a stable condition, according to the statement. Organizers said that all Olympic accommodation and buses were being disinfected.

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