The body of a fourth victim has been found following an explosion and fire that destroyed a New Jersey house and seriously injured two children, who were pulled from the fire by civilians, authorities said.

The cause of Thursday morning’s explosion in Buena, about 70km southeast of Philadelphia, is being investigated. It damaged several nearby homes, but no other injuries were reported.

The explosion. Photo / AP

Authorities had previously said those likely in the house at the time included two men, ages 52 and 73, and two children, a 2-year-old boy and a 3-year-old girl. A 1-year-old girl and a 16-year-old girl pulled from the fire by civilians were flown to a Philadelphia hospital, where the infant was in critical condition and the teen was stable, police said.

Authorities have not released the victims’ names or said whether they are related.

Three of the four missing people had been found dead in the rubble by 8pm. Thursday, Franklin Township police said. The body of the fourth victim was found at the base of the burned structure.