Members of a crisis negotiation team were deployed to the Stillwater correctional facility on Sunday.
A spokesperson for the state's Department of Corrections (DOC) said the reasons behind the incident "remains unclear".
But advocates say the move is in protest over prison conditions.
Excessive heat, limited access to showers and ice and unclean drinking water are among the reasons cited for the incident which took place in one of the facility's living units on Sunday.
