A fire at the Turkish Cypriot hospital Burhan Nalbantoğlu, in the north of Nicosia, led to the evacuation of 300 patients, as two people died after being transferred to a private hospital.
Two male patients aged 62 and 74, who were being treated in ICU when the explosion occurred, died after arriving at another hospital.
The fire which started around 6.45 am on Friday at the cardiology department spread panic among patients, with authorities evacuating the hospital and transferring patients who needed urgent treatment to nearby private hospitals.
It is unclear whether the deaths were caused by the transfer procedure.
Turkish Cypriot authorities have yet to determine the cause of the fire, but it is believed to have started after an explosion of an oxygen bottle.
The blast destroyed the entire cardiology department.
Turkish Cypriot police said the fire was under control and the fire department is working on cooling the area so investigations can get underway.
Turkish Cypriot health chief Ali Pili told reporters that a crisis committee has been set up and that authorities successfully evacuated the hospital.
Cyprus Health Minister Constantinos Ioannou said he contacted the Turkish Cypriot authorities through the bicommunal Technical Committee on Health and has offered to assist in the crisis if requested.