The Atlantic Institution in Renous is under a partial lockdown after an inmate was assaulted at the maximum security prison on Thursday night.
The Blackville RCMP and Correctional Service of Canada are investigating, Nicole Gaudet, assistant warden of management services for the institution said in a statement on Monday.
No staff members or other inmates were injured during the incident, which occurred at about 10 p.m., said Gaudet.
The inmate was evaluated by staff members and transported to an outside hospital for treatment, and the warden ordered the partial lockdown, she said.
"Normal operations will resume when it is considered safe to do so," the statement said.
"The safety and security of institutions, their staff and the public remains the highest priority in the operations of the federal correctional system," it said.
Atlantic Institution, which has a triangular design, houses up to 235 men in "direct observation living units," according to the website.