Authorities said the man attacked several prison workers and other inmates at around 10.15 a.m., injuring a nurse and a correctional officer so badly that they died.
Only additional security personnel were able to tame the prisoner. Paramedics who had rushed over could no longer help the two victims.
The Iowa law enforcement agency has not disclosed any further details for the time being.
Iowa’s Governor Kim Reynolds tweeted that the state was mourning “two civil servants attacked while on duty.” Their prayers and condolences would go to their families, friends and colleagues.
Everything will now be done “to bring justice to those who have committed this”.