Anti-corruption group sues Cheney

The group, Judicial Watch, claims Mr Cheney deceived investors while he was a director of the oil company Halliburton in the 1990s.

In a case being filed in Dallas, Texas, Mr Cheney is alleged to have engaged in practices which led to the overvaluation of the company's shares.

The move comes only a day after President Bush tried to distance himself from corporate fraud, proposing tougher penalties in an effort to restore confidence after the recent business scandals that have shaken the US.

Judicial Watch is also suing for access to records of Mr Cheney's energy task force that drew up the Bush administration's energy policy last year.

"To look the other way for the vice-president would be to set a precedent that the Washington elite are above the law," said Larry Klayman, chairman at Judicial Watch.

But Halliburton spokeswoman Wendy Hall said, "We don't believe the case has any merit."

Further details of the lawsuit are likely to emerge during a news conference in Miami on Wednesday at 9am local time (1300 GMT).

Harsher punishments

In a speech in New York's financial district on Tuesday, President Bush said he wanted to tighten measures against corporate fraud.

He announced a doubling - to 10 years - of the maximum prison sentence, and the formation of a special investigative task force.

But Judicial Watch said that Mr Bush's rush to crack down on corporate fraud seemed intended to deflect attention away from his and Mr Cheney's own business practices.

Mr Bush has already faced questions about his work as a director of Texas-based Harken Energy Corp a decade ago, when the firm faced an inquiry for masking huge losses.

His administration has been further embarrassed by a promotional video recorded by the Andersen firm in 1996, in which Mr Cheney - the then chief executive of Halliburton - praises the now disgraced audit company.

"I get good advice, if you will, from their people based upon how we're doing business and how we're operating. Over and above the just sort of normal - by-the-book - auditing arrangement."

Correspondents say the video is not the best advert for the Bush administration trying to distance itself from America's boardrooms, and that its business connections are fast becoming a serious liability.