A Minnesota prison was placed on emergency lockdown on Sunday after about 100 prisoners refused to return to their cells, authorities say.

The Minnesota Correctional Facility – Stillwater houses roughly 1,200 inmates, and around 100 inmates participated in the group protest. A spokesperson told the Associated Press that the reason for the prisoners' refusals "remains unclear."

The Minnesota Department of Corrections told FOX 9 Minneapolis that the prison's staff members were removed from common areas. A Special Operations Response Team was also deployed to handle the crisis.

Two prison officers were in a secure control area as of Sunday afternoon, and have been in contact with authorities.

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The situation is considered stable, FOX 9 reported. There are no confirmed injuries.

Fox News Digital reached out to the Minnesota Department of Corrections for a statement, but has not heard back.

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This is a breaking news situation. Check back with us for more updates.

The Associated Press contributed to this report.