ANKARA, August 3, 2008 (AFP) - Twenty-seven newborn babies have died over the past 15 days at a state hospital in Ankara, doctors said Sunday as trade unions blamed poor sanitary conditions for the deaths.

Hospital managers, who initially said that about a third of the deaths were caused by infections, told a press conference later that tests on samples from the babies produced no trace of an infection.

The babies, all prematurely born, died at Ankara's Zekai Tahir Burak Hospital for a variety of reasons, including hypertension, heart failure and complications at birth, said Ugur Dilmen, the chief phyician of the newborns' unit.

'The tests indicate nothing abnormal,' the Anatolya news agency quoted Dilmen as saying.

Dilmen also said that a total of 47 babies of the 504 treated in the hospital had died during the month of July.

He pointed out that the hospital is one of the busiest in Turkey, handling risky cases from all over the country, and ruled out any negligence on the part of doctors.

Dilmen said almost 4,500 babies were treated at the hospital last year.

But the SES health workers union charged that an infection outbreak caused by poor sanitary conditions was the likely cause of the deaths, insisting the 27 babies died over a three-day period -- between Thursday and Saturday last week -- and not over 15 days doctors had said.

The hospital's delivery unit had been relocated to a rundown part of the building due to renovation work and was prone to infections, the head of the Ankara branch of SES, Ibrahim Kara, told AFP.

He criticised the hospital authorities for failing to limit the number of patients received there during the renovation work, leading to overcrowding that would have worsened any outbreak of infection.

'Two or three women are made to wait on the same stretcher before giving birth and sometimes three newborn babies are put in the same incubator,' he said.

SES was the first to draw attention to the deaths, claiming the hospital sought to cover them up.

Alarm over the standards in Turkish hospitals was initially raised in 2005, when eight premature babies died of a bacterial infection in a hospital in the northwestern city of Edirne.