Updated

BUCHAREST, Romania (AP) — A fourth baby died Tuesday and seven remained in critical condition following a fire at a Bucharest maternity hospital that the health minister called "one of the darkest tragedies" in Romania's health system.

Authorities launched an investigation to determine the cause of the late Monday blaze at Giulesti maternity hospital, which forced the evacuation of dozens of babies and women — some in labor. The accident provoked a wave of public indignation, throwing light on Romania's poorly funded and understaffed health system.

Thousands of doctors have left Romania in recent years for better paid jobs abroad. Hospitals are understaffed and cannot hire, as the government battles a sharp economic downturn and tries to keep the budget deficit down.

Reports of hospital patients who have to buy bandages, medicines and syringes abound in the Romanian media. Even some doctors concede they lack things like surgical thread and so cannot perform surgery unless the patients buy it.

Romanian media reported the fire may have started due to a malfunctioning air conditioning unit.

Health Minister Attila Cseke called the accident was one of the "darkest tragedies in the history of Romania's health care system."

He said 53 babies and 61 women — some in labor — were evacuated to other hospitals.

Cseke said the hospital will stay closed until the investigation is finalized.

Health ministry official Raed Arafat said authorities will confirm the identity of all babies through DNA samples, after the plastic bracelets they wore for identification melted in the fire.

The manager of Grigore Alexandrescu hospital where the injured babies are being treated said they have burns on 40-80 percent of their bodies. The baby who died early Tuesday had burns on 80 percent of its body and also had a heart condition from birth, Radu Balanescu said.

Gabriel Patrascu, a father visiting his wife at the hospital, told news channel Antena 3 that no medical staff were in the intensive care unit when the fire broke out. Maternity hospital manager Bogdan Marinescu could not confirm the report.