A government prosecutor told jurors that defendants in the Enron fraud and conspiracy trial told "lie after lie" to conceal severe financial problems at their company and fool investors.

The opening statements came Tuesday in federal court in Houston, Texas. Former top Enron executives Ken Lay and Jeffrey Skilling face dozens of charges in connection with the collapse of what was once the largest energy trading company in the United States.

Enron went bankrupt in 2001, throwing thousands of people out of work and costing investors tens of billions of dollars. 

Some other key Enron executives have pleaded guilty to fraud and may testify against Lay and Skilling.

The defendants say they are innocent.

Some information for this report was provided by AP .