The British financial trader accused of manipulating markets and causing the 2010 "Flash Crash" in US stocks pleaded guilty in a Chicago court on Wednesday to fraud charges.

Navinder Singh Sarao, a 37-year-old working out of a modest suburban home in Hounslow in west London, allegedly made tens of millions of dollars with a computer program that could automatically manipulate prices.

He was extradited to the United States on Tuesday and entered the guilty plea to one count of wire fraud and one count of "spoofing," an illegal stock manipulation technique, in the Chicago federal district court, the Justice Department said.

"Navinder Sarao abused sophisticated technology to make a quick profit, and jeopardised the integrity of US financial markets," said Assistant Attorney General Leslie Caldwell.