A fire breaks out early Monday in Seonbu-dong of Danwon-gu, Ansan, Gyeonggi Province. (Gyeonggi Province Fire Services)

Four Nigerian children were killed in a fire early Monday in Ansan, Gyeonggi Province. The two girls aged 11 and 4, and boys aged 7 and 6 were siblings.

The fire broke out around 3:28 a.m., and was put out at 4:16 a.m. by firefighters at the second floor of the three-story residential building in Seonbu-dong of Danwon-gu in the city just southwest of Seoul.

Three more Nigerians including the parents of the deceased children, two Uzbeks and a Russian sustained injuries, and 37 people were evacuated.

The bereaved parents sustained burns and are receiving medical treatment at a hospital. Their youngest child -- a 2-year-old girl -- evacuated with the parents.

Police and fire authorities are looking into the cause of the fire.