1 person dead as explosion damages several homes in US' Pennsylvania

At least one person was killed and several others were left unaccounted for after an explosion destroyed three houses and damaged at least a dozen more on the outskirts of Pittsburgh, Pennsylvania on Saturday, CNN reported citing the local authorities.

The first responders who rushed to Plum, a borough in Allegheny County, found people trapped under debris and took three people to a hospital. One among them continues to be in critical condition, the officials said.

Another person, who has not been identified, was pronounced dead at the scene, said Steve Imbarlina, assistant chief for Allegheny County Emergency Services.

Apparently, the incident started when one house exploded, engulfing two neighbouring homes in flames as well, CNN reported citing the county. Multiple other homes also got damaged with windows blown out.

Crews from 18 different fire departments rushed on the scene to put out the flames and sift through the rubble as "several" people remained unaccounted for Saturday afternoon.

However, it has still remained unclear what triggered the explosion, as the authorities say that the cause is still under investigation.

The visuals show one of the homes exploding in a ball of fire, shooting up a thick plume of smoke and scattering debris in the area.

The aerial footage of the neighbourhood shows three structures completely burned to the ground, surrounded by heavy debris that covered surrounding lawns and homes. Several cars near the scorched area could also be seen charred black and smoking, CNN reported.

By 4:30 p.m. (local time), the area was still considered an "active scene" and first responders were expected to remain there for hours, according to the county. Plum is about 15 miles northeast Pittsburgh.

Gas was turned off in the area while emergency crews worked at the scene, authorities said at a news conference, adding multiple representatives from different gas companies were at the scene. The Red Cross and Salvation Army are also assisting residents impacted by the explosion, the county said, according to CNN.