The Japanese embassy in Washington has been assured that reports that the US Treasury Secretary, Mr Robert Rubin, was being held hostage in Tokyo until he said something nice about the Japanese economy are just a joke.

Mr Rubin's fictional ordeal was the main story-line in a spoof video, celebrating his departure from the Treasury post, shown to President and Mrs Clinton and friends at the White House. Real-life personalities putting in appearances in the video include Mr Larry Summers, who was sworn in as Mr Rubin's successor last Friday, and the Federal Reserve chairman, Mr Alan Greenspan.

The President makes a cameo appearance engrossed in a crossword puzzle - a favourite pastime - and thus too busy to worry about Mr Rubin, who will only tell his Japanese captors: "My name is Bob Rubin. I am a US citizen. Markets go up and markets go down. I have nothing more to say."

In the video, Mr Rubin is held captive by angry Japanese officials in the luxury Okura Hotel in Tokyo. As he stubbornly refuses to say anything positive about the Japanese economy, Washington goes into high alert.

The Defence Secretary, Mr William Cohen, appears at the Pentagon to announce that he will use the Navy's entire $82 billion budget to pay for Mr Rubin's hotel room in the Okura.

National Security Adviser Mr Sandy Berger, arguing with the Treasury that his name should appear first on an options memo to the President about Mr Rubin's fate, is shown as saying: "If we can't agree on this, then let him fry."

The Rev Jesse Jackson, renowned for his skills in procuring the release of American hostages, is called in "to find common ground between the yen and the yang". He is finally successful and declares: "Free at last, free at last. Thank God almighty, Bob's free at last."

A White House official told Reuters that the video was "really funny, but you'll never get to see it". It has become "super-classified". But as leaks began to appear in the Washington press, the producer of the video, Mr Gene Sperling, chief economic adviser to the President, contacted the Japanese embassy to assure them that it was just a joke and no harm was meant.

The Japanese diplomats have taken the spoof in good part. "They thought it was really funny, just like everyone else," a White House official said.