The state prison in Stillwater on Tuesday afternoon ended its facility-wide lockdown, which began Saturday in the wake of a fight among inmates, a spokeswoman said.

No staff members or inmates at the men’s prison were hurt, said Department of Corrections spokeswoman Sarah Fitzgerald.

As of Tuesday afternoon, “Stillwater is returning to normal operation except the housing unit where the incident occurred,” Fitzgerald said. “This unit will remain on lockdown until the [internal] investigation is complete.”

Citing the ongoing investigation, Fitzgerald declined to say how many inmates were involved in the fight, what prompted the incident or whether anyone has been charged.

There are roughly 1,600 inmates housed at the Stillwater prison, where many of the state’s most violent offenders are serving their sentences.