Babies and mothers in the neonatal unit at Basingstoke and North Hampshire hospital were taken to safety after reports of a fire.
Fire crews were called at around 9:30pm last night and fire engines from Basingstoke, Tadley, Odiham, and Kingsclere attended the scene. Staff at the hospital successfully evacuated the ward.
There were reports of steam and a smell of burning on the ward but no fire was found. The alarms were set off by an overheating pump, the fire services said.
Hampshire Hospitals NHS Foundation Trust said all maternity services are suspended while the investigation continues.
According to the Hampshire Fire and Rescue Service, no babies or mothers were injured.
Chief Executive Alex Whitfield said: “We apologise for the inconvenience and concern this incident has caused, both for the families of babies being treated in the neonatal unit and women using our maternity services.
“I’d like to thank Hampshire Fire and Rescue Service for their help and all of the staff who ensured that the babies were evacuated quickly and safely.”
Women in labour are being advised to attend Royal Hampshire County hospital in Winchester, while mothers and babies who were evacuated from the building last night are being treated elsewhere in the hospital.
The hospital is hoping that services will resume as soon as possible.