A devastating fire tore through a home in Waldorf, Maryland, early Sunday morning, killing four children and two adults, according to local authorities.

The blaze broke out in the single-family residence in Charles County, roughly 55 miles south of Baltimore. Fire crews responded quickly, but the intense flames and heavy smoke made rescue efforts extremely difficult.

One individual managed to escape the burning home and was treated for non-life-threatening injuries. The victims’ identities have not yet been released, and the cause of the fire is under investigation by the Maryland State Fire Marshal’s Office.

Neighbors reported waking up to the sound of sirens and seeing the home fully engulfed. “It happened so fast—within minutes, the whole house was in flames,” one resident said.

Officials have called the tragedy one of the deadliest residential fires in the region in recent years. Local support services are offering counseling and assistance to grieving relatives and community members.