Montgomery retired in 2005 after a doping ban

Montgomery, 32, pleaded guilty to one count of conspiracy to commit bank fraud and two counts of bank fraud.

"I sincerely regret the role I played in this unfortunate episode," he said in a statement.

Montgomery was a gold medal winner in the 2000 Olympics, but his career ended in 2005 after a doping scandal.

Following the plea deal, Montgomery is due to be sentenced in November and could get between three and four years in jail, defence lawyers said.

'Truly sorry'

"I have disappointed many people and for that I am truly sorry. I look forward to moving past this event and being a positive influence in my community in the future," Montgomery added in his statement.

Montgomery ran 100m in 9.78 seconds to break the world record in 2002.

He was also part of the winning 4X100m US relay team at the 2000 Sydney Olympics.

Montgomery was charged last year with his coach Steven Riddick and 11 others over an alleged conspiracy to deposit $5 million (�2.5m) in stolen, altered or counterfeit cheques.

The athlete allegedly deposited three bogus cheques worth a total of $775,000. He was accused of helping Riddick deposit others, and is reported to have accepted a $200,000 fee for his role.

Riddick, a medallist at the 1976 Olympics, has maintained he is innocent, AP news agency reported.

His trial is due to begin on Tuesday.