Power outages caused by a strong earthquake that rocked Hokkaido early Thursday wreaked havoc at hospitals across Japan's northernmost main island, with an infant girl briefly falling into serious condition after her oxygen inhalator stopped.

According to the health ministry, 349 hospitals lost power after the magnitude 6.7 quake. Many were forced to turn off equipment and turn away patients. There was no running water at 62 hospitals.

(A power outage in central Sapporo)

The girl, who is less than a year old, was moved to a different hospital and is in better condition, according to a Sapporo city official. The city is looking into the circumstances that led to her loss of oxygen.

All 34 hospitals in the prefecture designated by the government as key medical care facilities in the event of a natural disaster were running on electricity from emergency generators.

Tomakomai City Hospital, one of the so-called disaster base hospitals, was using a large gas-fueled generator to provide basic services, but turned off equipment such as MRI machines to save power.

"We've become unable to provide medical care that is 100 percent. I hope power is restored soon for the sake of the community," said Kaoru Sasaki, an administrator at the hospital.

(A blacked-out shelter in Sapporo)

The Chitose City Hospital was also using an emergency generator, but the limited output meant it had to turn away outpatients to prioritize care for the hospitalized. Staff said they had enough fuel for another 24 hours but expressed concern that the power grid may not come back online by then.

"What do we do then?" a worker asked.

The turmoil particularly affected those with liver conditions, who were unable to receive dialysis treatment.

According to the Japanese Association of Dialysis Physicians, 16 hospitals in Hokkaido were unable to treat patients requiring dialysis, which substitutes for the kidney in removing water and toxins from the bloodstream.