The blaze broke out at the Papanikolaou hospital on Wednesday morning.
Two people have died and at least one other was seriously injured after a fire at a hospital in northern Greece.
The blaze broke out on Wednesday morning in the COVID-19 ward of the Papanikolaou hospital in Thessaloniki, firefighters said.
The body of one person was found on the second floor of the health centre, they added. The Greek health ministry has reported that the victim was a 79-year-old patient.
Authorities later confirmed on Thursday that a 52-year-old man had also died of his injuries.
One more patient is being treated for burns in the hospital, while two more COVID-19 patients are under enhanced observation after smoke from the fire exacerbated their condition.
Authorities said that they had evacuated 34 patients who were being treated in the hospital ward.
Video footage from the site showed thick black smoke billowing out of two windows on a lower floor of the facility and firefighters clambering up to the windows.
An investigation has been launched into the cause of the blaze, which was extinguished by mid-morning.
“The danger was from the oxygen supply to the patients, that could have made the situation much worse,” Health Minister Thanos Plevris told reporters outside the hospital Wednesday.
“The supply was cut off quickly and the response from the fire department was swift,” he added.