CRANSTON, R.I. (WPRI) — An investigation is underway after a fight between two ACI inmates spurred a lockdown Friday night, 12 News has learned.

Ryan Crowley, a spokesperson for the Rhode Island Department of Corrections, tells 12 News the fight broke out in Maximum Security just before 7 p.m.

Crowley said a correctional officer suffered minor injuries while breaking up the fight. That officer was treated offsite and has since returned to work.

Several officers in tactical gear were seen rushing into Maximum Security with batons and shields.

Crowley said the ACI remained on lockdown due to “several dozen” inmates refusing to leave the facility’s secure yard.