BAGHDAD, Aug. 10 -- At least 20 newborn babies were killed on Wednesday in a fire at a hospital in the Iraqi capital of Baghdad, a police source told Xinhua.

The incident took place at dawn when a fire broke out at the maternity wards in Yarmouk Hospital in western Baghdad, the source told Xinhua on condition of anonymity.

"The children mainly died of suffocation from the thick smoke which spread in the wards," the source said.

The fire is under investigation, but initial reports said that it was probably caused by "electrical contact," the source added.