Authorities have recovered the bodies of two young cousins who were trapped when a wall of dirt fell on them while playing in a hole at a home construction site in North Carolina.

Lincoln County Emergency Services spokesman Dion Burleson said the bodies of a 6-year-old girl and 7-year-old boy were pulled early Monday from a 24-foot-deep pit in the town of Stanley, outside of Charlotte.

"These are horrific circumstances," Burleson told reporters gathered near the rural site on a two-lane road.

Crews had been searching for the children since Sunday afternoon, when one of their fathers called 911 to report the collapse. Officials were on the scene within minutes but couldn't get to the children.

The father had been digging with a backhoe on the site earlier in the day, Sheriff David Carpenter said. He would not say what was being built or if the man was doing it alone or had professional help. He did say authorities didn't know of any permits that had been issued for the work or plans detailing the project.

Burleson described the pit as 20 feet by 20 feet with a sloped entrance leading down to the 24-foot bottom. Carpenter said the children were at the bottom of the pit retrieving a child-sized pickaxe when the walls fell in on them.

The children's names have not yet been released. According to the Charlotte Observer, the first 911 call came at 5:07 p.m. Sunday from the boy's father, identified as Jordan Caldwell.

Carpenter told the newspaper that "There were several thousand pounds of dirt on top of them."

He said his deputies would continue to investigate what happened. In a Lincoln County Sheriff's Office news release, the children were identified as James Levi Caldwell, 7, and Chloe Jade Arwood, 6.

In an interview with The Associated Press, Carpenter later said deputies had not yet interviewed the family living in the home but planned to follow up on neighbors' reports that the man was excavating the two-story pit to build some sort of a protective bunker.

They were so distraught we hope to be able to talk to them today and come up with some information on that," Carpenter said. "It's a very large hole. It would look to be something like that, but I don't know. ... We're going to find out exactly what his intentions were."

He said deputies would be speaking with county planning and zoning officials about any potential building code violations at the site.

Neighbor Bradley Jones said the children often played in the pit when the boy's father was working there. Jones, who said he works in construction, said there was no structure to support the pit's tall dirt walls and that he questioned the man about the hole's depth.

"I told Chelsea not to go in," Jones said, referring to advice he gave his teenage daughter, who babysat the children. "It was dangerous. There was nothing to reinforce those walls."

The Associated Press contributed to this report.