Houston (Texas): A former executive at Enron Corp pleaded guilty to conspiracy to commit wire fraud and money laundering, in what officials called a milestone in their efforts to build a criminal case against the bankrupt energy trader's former management.

Michael Kopper, 37, also agreed to co-operate with authorities in their probe into the spectacular collapse of the energy trader late last year, and forfeit $ 12 million.

"Today Michael Kopper has accepted personal responsibility for his role in the Enron tragedy," said his lawyer David Howard.

"Michael hopes that these actions demonstrate his deep regret for his own conduct. He apologises to all whose lives have been affected by what he did."

Under his plea agreement with prosecutors, the former managing director of Enron Global Finance admitted using his position at the Houston-based company to enrich himself and others, Howard said.

In his position as director of Enron's off-balance-sheet partnerships, Kopper used his authority to siphon off millions of dollars for both himself and his boss, Andrew Fastow, Enron's former chief financial officer, according to the official chargesheet.

When he quit in August 2001, for example, Kopper pocketed $ 10.5 million from a partnership called Chewco, after investing just $ 125,000 of his own money in it.

On one occasion, he also wired more than four million dollars from one of Enron's off-balance-sheet partnerships to a bogus charity set up by Fastow.