Sand Dunes
Mesquite Dunes in Death Valley National Park, California (Reuters)

A six-year-old boy was trapped underground for about three hours when a sinkhole opened up at Indiana Dunes National Lakeshore in the US.

The boy, who got trapped under 11 feet of sand while playing in the area on Friday afternoon, is believed to be from Illinois. Firefighters and police had to use heavy equipment to pull the boy out, during a rescue operation that lasted for three hours.

According to officials, the boy was saved because of an air pocket around him, even as he was trapped beneath sand.

The boy was initially taken to Franciscan St. Anthony Health Medical Center and later air lifted to Chicago hospital where he is in "pretty good shape," Lakeshore Ranger Bruce Rowe said.

"I have never heard of anything like this here or at other sand dune parks," Rowe added.

A press release from First Baptist Church of Galva, Illinois revealed that the boy's name is Nathan Reul, and his grandfather, Don Reul, is a pastor at the church, Mail Online reported.

Nathan was walking with his family along the sand dunes in Michigan City when he stopped near a rotten tree, which perhaps caused the sinkhole, WRTV-TV, Indianapolis, reported.

A report by The Indy Channel said that the child fell partially into the hole while playing on a dune restricted to public access, and the whole thing collapsed on him when his parents were trying to pull him out.

The boy's parents immediately called emergency number 911 and within 15 minutes, emergency crews were digging the area.

Nathan started breathing and crying on the way to the hospital, ABC 57 reported.

The area will remain closed until an investigation into the matter is completed.

The child has ingested plenty of sand, and may have to go through extensive therapy to restore his lungs, Laporte County chief deputy coroner Mark Huffman told ABC News.