An inmate from the Massachusetts Treatment Center in Bridgewater died Thursday after being treated for COVID-19 at a hospital, the state Department of Correction said.

State officials declined to provide the inmate’s name. He was in his 50s with “underlying health conditions” and his next of kin have been notified.

The inmate was the first known death in the state prison system related to the virus, part of a spreading contagion in the Massachusetts Treatment Center where the first case was announced nearly two weeks ago.

On Thursday, state officials said 23 inmates as well as three DOC staff members and a medical provider at the facility were confirmed with the virus.

They are among 34 staff and inmates in the state prison system to have confirmed cases on Thursday, up from 28 the day before, according to state officials.

One other inmate and a DOC worker have confirmed cases at the Massachusetts Correctional Institution in Shirley.

Both facilities are currently on lockdown, state officials said. Another four staff members and a medical provider have been confirmed with the coronavirus at other facilities in the system, including MCI-Framingham, the Souza-Baranowski Correctional Center and the administration’s central office.

Coronavirus cases are also spreading among employees in the state’s 13 county jails, with 20 confirmed COVID-19 cases. Two inmates also have tested positive, according to the Massachusetts Sheriff’s Association.

The rise in confirmed cases comes as defense attorneys, prosecutors and prisoners advocates await word from the Supreme Judicial Court, which is considering an emergency petition to release some inmates who don't pose a risk to public safety to reduce the prison population and prevent the spread of the virus.