A 20-year-old man dressed in camouflage went on a shooting rampage in a mall crowded with holiday shoppers, killing eight persons and wounding five others, before turning the rifle on himself in the United States' Nebraska state.

Hundreds of panic-stricken shoppers ran to bathrooms, hid under display racks and crouched behind garbage cans as Robert Hawkins, who left a suicide note that said, "Now, I will be famous", sprayed bullets from his SKS assault rifle while perched on a third floor balcony.

"All I could think was 'what if he comes through the door, what if he comes through right now?'" said Kevin Keline, 29, who hid in a storage room with her four-year-old daughter and four other women, including an expectant mother, as the gun shots rang out in a retail store inside the Omaha mall.

The deceased included five men and three women. Police said the Wedneday afternoon attack appeared to be premeditated but without provocation and that the gunman was acting alone.

ABC television channel reported that the man had two magazines taped together, a technique used for faster reloading of the gun.

President George Bush [Images] was at an Omaha fundraiser, but had left about an hour before the incident. The incident came almost eight months after the deadliest shooting at Virginia Tech University, in which a student killed 33 people.

Friends and neighbours said Hawkins had had trouble in school. He had broken up with his girlfriend and had lost a job recently at a McDonald's fast food restaurant.

"I had just learned that he had been fired and this must have triggered all of this," Hawkins' landlady Debora Maruca-Kovac said.

Kovac claimed that he had written a suicide note which said he was 'sorry for everything' but added 'now I will be famous' and wanted to go 'in style'.

The shooting rampage is the worst in the state's history and the latest to shock the United States, which has seen several such incidents in recent years. It is the fourth mall or shopping centre shooting in 2007 itself.

The incident is likely to rekindle the debate whether there should be more control on sale and possession of guns, which has been opposed by the powerful gun lobby.

The gun lobby argues that a person who has criminal intent can always get the weapon even under the strictest control.

With dodging bullets being the last thing on their mind, shoppers who had thronged the mall three weeks ahead of Christmas, thought that the shots were construction noise.

"With all the construction work going on, it sounded like nail guns. But then people started running out frantically saying there has been a shooting. I gathered my wife and kids to rush out," said Shawn Vidlak.

"I heard loud booms. I don't think anyone believed it was gunshots. We heard about 35 to 40 shots," said Jennifer Kramer who was in Von Meur store where the firing took place, with her mother hiding in a clothes rack.

The corporate headquarters of Von Maur issued a statement saying that it was deeply saddened by the horrific shooting.