Image caption The fire reportedly broke out on the ground floor

A fire broke out in a hospital in southern Japan early on Friday, killing 10 people, police said.

Eight patients and two hospital workers died in the blaze that hit the hospital in Fukuoka prefecture, police said.

The fire reportedly started on the ground floor of the four-storey building at 02:20 am (17:20 GMT) and took more than two hours to put out.

Reports say at least 17 people were in the orthopaedic hospital when the blaze broke out, including elderly patients.

"The cause of the fire is yet to be determined," a police official said.

An eyewitness told local media that the ground floor of the hospital "was red with flames and was filled with smoke. The part where beds were located seemed to be burning".

During a press conference, a fire station official told reporters: "We did our best in fire-fighting to save lives... but it was a difficult situation."

"We received news of the fire at a very late stage, and there had been no attempt [by staff] to tackle the fire in its early stages."

"Patients... were exposed to a lot of smoke because fire doors that would have stemmed the flow had been left open," he added.

"We will start an investigation [into the source of the fire]."

At least five other people were injured by the fire, officials said, with several reportedly in a critical condition.