A US gunman and murder suspect who snatched a five-year-old boy and held him for a week underground in a bunker besieged by police has been killed and the child is safe, media reported Monday.

The end of the siege was confirmed by CBS News and CNN, citing federal authorities. Live television footage from the scene showed increased police activity, but there was no clear view of the bunker.

Police had earlier identified the abductor as Jimmy Lee Dykes, a 65-year-old retired trucker. The motive of the January 29 abduction in the town of Midland City in the southern state of Alabama remained unclear.

Dykes is said to have shot dead the driver of a school bus and seized his young hostage, retreating to an underground room on his property and defying calls for his surrender.