The move would not require her to be cross-examined at a public hearing of the House of Representatives investigating committee. She would be given a series of questions to answer in writing. The suspicion is growing that Mrs Clinton wanted the documents to discover if there was anything in the background of White House staff that might indicate they were capable of betraying her. She was apparently angered that someone, possibly one of her Secret Service bodyguards, leaked details of a vase-throwing argument with her husband.

At the heart of the affair is the identity of the person who originally hired the collector of the files, the former White house security chief Craig Livingstone, who acted as a "dirty trickster" in the 1992 Clinton election campaign. On a recent trip to Bucharest, Mrs Clinton said he did not have a hand in recruiting him. "I don't know about it."

One of her husband's aides, George Stephanopoulos, said on television that Mr Livingstone was appointed by Vincent Foster, the lawyer and close friend of Mrs Clinton found shot in mysterious circumstances in 1993. Congressman William Clinger, the Republican chairman of the investigating committee, said on CNN yesterday: "I would have trouble believing that." Of Mr Foster, he said: "He's a pretty good scapegoat."

He said Gary Aldrich, a retired FBI agent who worked at the White House, had spoken of a conversation with William Kennedy, a lawyer on the Clinton staff, who "suggested it was the First Lady" who wanted Mr Livingstone in charge of security. He said both men were to be questioned by the committee as to the truth of the accusation. He talked of the affair being "very suspicious", saying: "I think we will find out." Mr Clinger said that there was firm evidence to "suggest that Mrs Clinton was very directly involved in all of the personnel decisions having to do with the White House".