The Maine State Prison in Warren pictured in 2017. Credit: Ashley L. Conti / BDN

The Maine CDC has opened an investigation into a coronavirus outbreak in Maine State Prison in Warren after seven inmates were confirmed to have the virus, the Maine Department of Corrections reported Wednesday.

Two more inmates have also tested positive for the virus, but official confirmation of those cases is pending another round of tests. All inmates who have tested positive live in the same residential unit.

The case of a staff member reported Tuesday who tested positive for the virus was determined not to be part of the outbreak, according to the Maine Department of Corrections.

The Warren-based prison is the state’s largest correctional facility. It currently houses about 700 inmates, according to the department.