Police continued their investigation Friday into the cause of a fire that gutted a well-known inn at the Tsuchiyu Onsen mountain resort area in the city of Fukushima.

The fire Thursday night left one employee missing and destroyed the Hakuunso "ryokan," a traditional inn, and a nearby warehouse.

The police said the whereabouts of a female employee in her 50s remained unknown.

According to the fire department, five guests and four employees were staying in the inn when the fire broke out.

Among the eight people whose safety was confirmed, innkeeper Hisao Abe, 80, suffered an injury that was not life-threatening, the fire department said.

Meanwhile, a male guest in his 50s who was initially unaccounted for was confirmed safe. He reportedly drove out of the area.

Tsuchiyu Onsen is about 15 km southwest of the Fukushima city center. Hakuunso, a wooden structure, was built on a slope and had two stories above ground and one basement level. The inn had room to accommodate up to 46 people, including hotel personnel.

According to its website, Hakuunso was established in 1917. Among the guests who stayed there was noted poet and sculptor Kotaro Takamura, who visited the inn with his wife, Chieko.

The nearly 100-year-old building had withstood the Great East Japan Earthquake on March 11, 2011, without suffering major damage.