Indictment Threatens Bush Aide Over Cia Leak

There were signs last night that a criminal investigation into an intelligence leak was closing in on the White House after a federal prosecutor refused to rule out criminal charges against President George Bush's chief political adviser, Karl Rove.

The special counsel in the inquiry, Patrick Fitzgerald, accepted Mr Rove's offer to give unexpected new testimony, just days before the expected conclusion of a two-year investigation into the leak of a clandestine CIA agent's identity.

However, before accepting the offer, Mr Fitzgerald sent a formal letter to Mr Rove's legal team, saying that he could not guarantee that the presidential aide would not be indicted, according to the Associated Press, quoting "people directly familiar with the investigation".

Under US court procedures, such warnings are required before a witness gives evidence to a grand jury if there is a possibility that the witness could be charged. No such caution was issued to Mr Rove before his three previous appearances to testify in the case.

His lawyer, Robert Luskin, confirmed that Mr Rove intended to testify voluntarily for a fourth time, but insisted that he had not received a "target letter" indicating that an indictment was imminent. "The special counsel has confirmed that he has not made any charging decisions in respect to Karl," Mr Luskin told the AP.

An indictment against Mr Rove would be an earthquake for the White House. He has been Mr Bush's closest political aide for more than 10 years, masterminding his election to the Texas governorship and then to the US presidency.

After the president hailed Mr Rove as "the architect" of his re-election last year, he was given the job of deputy chief of staff, with far-reaching power over the administration's policy as well as its political strategy.

The leak investigation was launched after the disclosure in July 2003 of the name of a CIA undercover official, Valerie Plame. Her husband, Joseph Wilson, a former US ambassador, claimed that her identity had been leaked by the Bush administration in retribution against him for publicly questioning the official justification for the Iraq war.

Matt Cooper, a journalist for Time magazine, told the grand jury in July that Mr Rove had told him on condition of anonymity that Mr Wilson's wife was a CIA agent and that she had been instrumental in sending her husband to Africa in 2002 to check claims that Iraq was buying uranium.

Judith Miller of the New York Times, last week named Lewis Libby, chief of staff to the vice-president, Dick Cheney, as her source for a similar story. Miller had spent 85 days in jail for refusing to cooperate with the investigation.

Both officials have said they did not disclose Ms Plame's name, and were not aware that she was working under cover.