New Delhi, Aug. 27 -- Investigators appointed by Pakistan's prime minister were making a visit Thursday to the hospital nursery where a fast-moving fire killed 14 newborns, as grieving families and the public sought answers about the cause of the blaze and the safety measures at the major government facility.

The fire early Wednesday was confined to the third-floor nursery and did not affect the rest of the facility. Hospital officials said the fire spread so quickly the two doctors, two nurses and other staff present were able to rescue only one baby among the 15 in the nursery.

The scene at the Pakistan Institute of Medical Sciences in Islamabad was somber Thursday as doctors, staff, patients and relatives mourned the newborns. Access...