WASHINGTON, Feb 05, 2013 (AFP) - A 5-year-old boy held hostage in an underground Alabama bunker for almost a week was rescued Monday in a raid that left the kidnapper dead, authorities said.

The boy, who has been identified only as Ethan, was rushed to safety and is "doing fine," an FBI agent told reporters in Midland City, Alabama.

Agents said they feared the boy was in "imminent danger" after seeing the kidnapper, retired trucker Jimmy Lee Dykes, holding a gun.

Negotiations with the gunman deteriorated, according to FBI Special Agent Stephen Richardson. So agents were ordered to storm the bunker at 3:12 pm (2112 GMT) central time.

"The subject is deceased," Richardson said of Dykes. The agent declined at a brief news conference to provide details on the kidnapper's death.

"We were certainly concerned for the safety of the child," Richardson explained. "He is very brave. And he is very lucky.

"The success story is that Ethan is with his mother right now," Richardson added.

Residents described hearing an explosion and shots.

"I heard a big boom and then ... I believe I heard rifle shots," Bryon Martin, who owns a house near the bunker, told CNN. It was a loud noise that "made me jump off the ground," he said.

Police have said Dykes, aged 65, boarded a school bus last Tuesday and when driver Charles Albert Poland tried to block him, shot the man dead. He then snatched Ethan and held him in a bunker on his property for six day as police tried to negotiate his release.

"It got really tough to negotiate with him," Dale County Sheriff Wally Olson told reporters after the rescue.

The boy was reunited with his mother at a hospital in nearby Dothan, Alabama. "He's laughing, joking, playing, eating -- the things you'd expect of a 5- or 6-year-old," Richardson added.

Man 'in bunker for up to 8 days'

Dykes -- a US Navy veteran who worked in aircraft maintenance in the 1960s -- had been known to stay in his underground bunker for up to eight days, neighbors, who have evacuated the area, told ABC News earlier.

They also told US media he had dramatic behavioral swings and anti-government views.

The slain bus driver, Charles Poland, 66, was described as a quiet man who enjoyed a simple life with his wife, Jan.

People who knew him said it was hard for Poland to discipline children on his bus when they misbehaved, an Alabama newspaper, the Dothan Eagle, reported.

"It says in the Bible the meek will inherit the earth," Poland's brother-in-law, Melvin Skipper, was quoted as saying. "He was the meekest man I knew."

It was yet another tragedy in the epidemic of gun violence in America, still reeling from the tragedy in Sandy Hook, Connecticut.

It has been more than six weeks now since the massacre of 20 children and six adults at a Connecticut elementary school again electrified the debate over guns in the United States.

President Barack Obama is urging Congress for action "soon" on curbing gun violence. Obama wants the renewal of the ban on military-style assault rifles and argues that it is time to restrict the sale of high-capacity ammunition clips that can fire off many rounds in seconds.

The president's plans are vigorously opposed by many Republicans, who believe he is watering down the constitutional right to bear arms, and by the gun lobby headed by the powerful National Rifle Association.

The NRA meanwhile has called for armed guards in all US schools.