Bush and Cheney top aides testify

Scott McClellan (left) and Karl Rove are among those called to testify

Senior aides to the US president and vice-president have been called before an inquiry into the leak of a CIA agent's name, according to reports.

Karl Rove, George W Bush's special adviser, and Lewis Libby who is Dick Cheney's chief of staff testified to a grand jury, the Washington Post said.

Two of Mr Bush's press officials have also appeared at the inquiry recently.

The investigation was ordered into the leak of the name of Valerie Plame who worked for the US spy agency.

A newspaper columnist revealed her name last summer, saying White House officials had given him the information about Ms Plame, whose husband Joseph Wilson has criticised the White House.

A deliberate leak of an undercover agent's name would be illegal.

Administration 'co-operation'

White House spokesman Scott McClellan confirmed he had testified to the grand jury investigating the leak as part of a federal investigation led by US Attorney Patrick Fitzgerald.

Joe Wilson, whose wife was named, now works for Democrat John Kerry

Adam Levine, a former administration press aide, also appeared at the inquiry, his lawyer told the New York Times.

Mr McClellan said: "I'm just doing my part to co-operate fully with the investigation.

"The president has made it clear that no-one wants to get to the bottom of it more than he does."

Sources said to be involved in the case were quoted by the Washington Post as saying other witnesses included Mr Rove, Mr Libby, former Cheney adviser Mary Matalin, White House communications director Dan Bartlett, former press secretary Ari Fleischer and Cheney press aide Cathie Martin.

Hundreds of e-mails, phone logs and notes were handed over from White House staff to the justice department investigation last year.

The New York Times said prosecutors were referring often to notes compiled by Mr Libby but added that investigators were not revealing any overall theory of the case.

Iraq claims

Journalists may also be called to testify amid allegations that White House officials called a number of correspondents seeking to place the leak.

Ms Plame's name became public after her husband, a former ambassador to Gabon, wrote an article revealing he had been sent to Niger by the CIA in 2002 but had found no evidence that Iraq had sought to buy uranium from the country.

In his State of the Union address in January last year, President Bush mentioned the uranium allegations as he built a case for war.

The White House has since admitted that Mr Bush's speech should not have included the charge, which he attributed to British intelligence.

Mr Wilson is now an adviser to Democrat presidential front-runner, John Kerry.