Pennsylvania: Explosion in nursing home, 2 dead, several missing

An explosion occurred in a nursing home located in a suburb of Philadelphia, Pennsylvania, USA, which resulted in a fire.
According to American media, a part of the nursing home collapsed due to the explosion. Authorities confirmed that 2 people were killed in the incident, while several are still missing.
The Governor of Pennsylvania said that after the incident, local rescue agencies, staff and citizens immediately moved the elderly to safe places.
Immediately after the explosion, gas and electricity supplies to the nursing home were cut off as a precautionary measure to keep rescue personnel and nearby residents safe.
In the initial investigation, authorities attributed the explosion to a gas leak, but investigations are underway to determine the final cause of the incident.