US President George W Bush authorised the leak of classified material to the media to defend the invasion of Iraq, a former White House aide has testified.
Lewis Libby is accused of lying to investigators
The testimony, cited in court papers, comes from Lewis Libby, who is facing trial in connection with a separate leak involving a CIA agent's identity.
Mr Bush, who is not accused of allowing the agent's outing, is under pressure to say if he was behind any other leak.
He has in the past condemned leaks and has said he would sack anyone involved.
The White House has so far failed to comment on Mr Libby's testimony.
Top Senate Democrat Harry Reid called the claim "shocking", and said Mr Bush "must fully disclose his participation in the selective leaking of classified information".
The BBC's Justin Webb in Washington says once again President Bush is fighting for his political credibility, with Democrats smelling blood.
Mr Libby's testimony marks the first time he has put Mr Bush into the frame of events surrounding leaks from the White House to the press over the Iraq war.
Mr Libby said he was told in July 2003, when he was chief-of-staff to Vice-President Dick Cheney, to give a reporter pre-war intelligence, court papers reveal.
He testified that Mr Cheney had told him to pass information from the classified National Intelligence Estimate to Judith Miller, a New York Times reporter.
CIA LEAK TIMELINE
6 Jul 2003: Joseph Wilson questions US claims about Iraq nuclear programme
8 Jul: Libby leaks classified information to reporter Judith Miller, but not agent's name, he later testifies
14 Jul: Columnist Robert Novak identifies Wilson's wife as CIA agent
30 Sept: Justice dept launches inquiry into agent's outing
28 Oct 2005: Libby charged with obstruction and perjury
6 Apr 2006: Court papers suggest Bush authorised leak of classified material (not agent's identity)
Mr Cheney is alleged to have said that the release of classified information had been approved by the president. Mr Libby said he understood this meant he had legal cover to discuss this material.
The aim of the leak, Mr Libby is reported to have said, was to rebut an article questioning some of the evidence used to justify the case for a US-led invasion of Iraq.
The article was written by former diplomat Joseph Wilson, the husband of the undercover agent Valerie Plame who was subsequently outed.
Court papers quote Mr Libby as saying he did not discuss Ms Plame during his 8 July meeting with Miller.
Mr Libby is charged with lying to investigators and obstructing the investigation into the leak of Ms Plame's identity.
He resigned as chief-of-staff to Mr Cheney after he was charged last year and is due to go on trial in January 2007.
No-one has been charged with a crime over the leaking of Mrs Plame's name to reporters.