POHANG (Yonhap News) ― One South Korean was killed and 14 others injured in a mountain fire that spread to residential areas in this southeastern coastal city of Pohang.

Police said they are interrogating a middle school student as a suspect.

The fire that started on a hill around 4 p.m. Saturday was almost extinguished by Sunday morning after burning nearly 5 hectares of mostly residential areas, according to firefighters.

The fire killed an 80-something person and left 14 others injured, the firefighters said. About 53 houses were destroyed in the fire.

More than a hundred people were evacuated while more than 2,000 firefighters, mobilized soldiers and government employees struggled to put out the fire, according to National Rescue Services.

The Pohang Bukbu Police Station said a 12-year-old middle school student is being questioned on suspicion of setting the fire.

The boy allegedly set fire to a pile of dry leaves at the foot of the residential area hill with two other friends. As the fire spread, they reported it to fire authorities and ran away, according to the police station.

A police official said, “We are interrogating them over whether their deliberately set the fire.”

Meanwhile, another mountain blaze was spreading Sunday in farming villages in Ulsan, 414 kilometers southeast of Seoul.

About 4,300 firefighters, soldiers and government workers, along with 11 helicopters, were sent to fight the fire that started in a mountain village late Saturday, but they are still struggling to extinguish the spreading fire, according to firefighters.

Three people were injured after inhaling smoke while hundreds of dogs and chickens were killed in the fire, which also consumed

23 buildings and houses and burnt 50 hectares of forests spanning several villages.

Hundreds of villagers evacuated to the three shelters designated by the city government.

Firefighters are working to put out the fire by noon while officials are investigating the exact cause of the fire and the scope of the damage.