Seven premature newly born babies - nearly half the number in a Turkish hospital’s intensive care unit - have died after contracting a bacterial infection, Health Ministry officials said on Monday.

“This is the first time we have seen such a case. We are looking for the source of this bacteria,” said Armagan Altun of Thrace University Medical Faculty hospital in Edirne, a town near Turkey’s borders with Greece and Bulgaria.

All the babies - six died over the weekend and the seventh on Monday - had been placed in an intensive care unit after being born prematurely, Altun said.

One of the nine other babies in the unit was in critical condition.

The health ministry has begun an investigation into the deaths, which received blanket coverage in the media.

Turks often complain of poor sanitary and hygiene conditions in the country’s overcrowded state hospitals.