Three British former bankers extradited to the United States this week pleaded not guilty in federal court on Friday to fraud charges linked to a deal with defunct energy giant Enron Corp.

Magistrate Judge Stephen Smith said he would release David Bermingham, Giles Darby and Gary Mulgrew, former employees of National Westminster Bank, pending a hearing scheduled for next Friday when he would rule on whether they should be allowed to return to Britain, as requested by their lawyers.

The court set the start of their trial for September 11.

Bermingham and Darby agreed to put up $100,000 and Mulgrew pledged $20,000 to secure their temporary freedom, and the men agreed to submit to electronic monitoring.

This is not in any way prejudging what the final bond amounts will be, Smith told the court.

The men appeared in court in their own clothes, a sharp contrast to the prison-issue green jump suits most defendants wear to such hearings. They appeared relaxed throughout the hearing, and each proclaimed not guilty in firm, clear voices when asked to enter their pleas by the judge.

The extradition of the NatWest Three, as the men have been dubbed in the media, has drawn criticism in Britain as an abuse of an extradition treaty that the United States has not yet ratified.

Critics of the treaty say it is unfair because the United States does not have to provide evidence to support extradition requests from Britain, but Britain must comply with a more stringent standard to seek extraditions from the United States.

British Prime Minister Tony Blair has defended the treaty from criticism by political opponents in parliament.

Lawyers for the three bankers argued in court that they should be released and allowed to return to Britain, where they could continue working.

But prosecutors said the trio should be restricted to the United States because they fought hard to avoid extradition and allowing them to return to Britain could facilitate another legal battle.

We believe the defendants pose a significant risk of flight, said prosecutor Leo Wise.

According to their 2002 indictment, Bermingham, Darby and Mulgrew conspired with former Enron Chief Financial Officer Andrew Fastow and his deputy Michael Kopper to estimate the value of its stake in a partnership at $1 million.

NatWest, now a unit of the Royal

Bank of Scotland, sold its interest to a Fastow-operated financial vehicle, and the three British bankers were ultimately paid $7.3 million on their investment of about $250,000.

Fastow and Kopper have pleaded guilty to crimes at Enron under cooperation agreements with prosecutors and are scheduled to be sentenced late this year.