The United States is categorically denying any connection with the cargo jetliner and its 64 passengers held since Sunday by authorities in Zimbabwe. A State Department official rejected Zimbabwean charges that the plane and the alleged mercenaries on board were part of a U.S.-related coup plot against the leadership of Equatorial Guinea.

A senior official in Washington says that neither the aging Boeing 727 cargo plane nor the 64 men Zimbabwe says were on board had any connection with the United States government, and he says claims to the contrary by Zimbabwean authorities are "utter nonsense."

The comments followed a charge by Zimbabwe's Home Affairs Minister, Kembo Mohadi, Wednesday that the aircraft and those aboard had been bound for Equatorial Guinea to take part in a plot backed by the intelligence agencies of the United States, Britain and Spain against the government of the tiny, oil-rich state.

The State Department official said the notion of U.S. involvement is "absolutely false" and that he spoke for all elements of the U.S. government on the issue

He expressed puzzlement as to why such "idle rumors" were being spread, and said despite the highly-publicized allegations from Zimbabwe, that government of President Robert Mugabe had not raised the matter with either the U.S. embassy in Harare or with officials in Washington.

There were similar comments earlier from Secretary of State Colin Powell who told a Congressional hearing U.S. officials knew nothing about the plane other than what they had heard in media accounts.

Mr. Powell also said under questioning that despite its strong political differences with Mr. Mugabe, the United States has no policy of "regime change" with regard to Zimbabwe. "We have no intention of going in and displacing President Mugabe. But are we disappointed in his leadership? Do we speak critically of his leadership? Yes, we do. And I have been for the three years that I've been Secretary, and think we all should," he said.

The Bush administration last week tightened its targeted sanctions against Mr. Mugabe and close associates, adding seven Zimbabwean companies linked to senior government officials to a list of firms whose U.S. assets, if any, are to be frozen.

The State Department said the sanctions target only those responsible for Zimbabwe's political crisis and not ordinary citizens. It urged the Mugabe government to "abandon political repression" and engage in meaningful dialogue with the opposition.