Gisslandrama i USA - 6-åring som gisslan i 3 dagar

Dykes has told authorities he has blankets and a heater in the bunker, and authorities have previously said the bunker -- built 4 feet underground -- has electricity.

Negotiations are being carried out between the suspect and authorities through a 60-foot plastic ventilation pipe that leads from the bunker, authorities said.

It's unclear whether Dykes has access to news reports about the standoff.

FBI Special Agent in Charge Steve Richardson at the scene said negotiations had broken down with the child's abductor and the kidnapper was "observed holding a gun."

Believing the child to be in imminent danger, an FBI team entered the bunker at 3:12 p.m. CT (4:12 p.m. ET) and rescued the boy, Richardson said, adding that the hostage-taker is dead.

One neighbor said he was outside when he was startled by the sound of an explosion.

"I heard a big boom and then ... I believe I heard rifle shots," said Bryon Martin, who owns a home near the bunker where the boy had been held since Tuesday.