President Bush has vowed to keep his administration focused on his economic and political agenda, following the indictment of a senior White House aide in the probe into who leaked a covert CIA operative's identity.

Mr. Bush said Friday he was saddened by the indictment and subsequent resignation Friday of vice presidential aide Lewis Libby. But Mr. Bush stressed that he and his staff had a job to do, to protect the American people.

A federal grand jury indicted Mr. Libby on five criminal counts - including making false statements, perjury and obstruction of justice - in connection with his testimony about who revealed the name of covert CIA operative Valerie Plame.

The special prosecutor in the case, Patrick Fitzgerald, has said the investigation is not over.

Ms. Plame's role in the CIA was leaked to the media after her husband, diplomat Joseph Wilson, accused the Bush administration of manipulating intelligence to justify the Iraq war. Mr. Wilson says the White House exposed his wife's CIA work in order to punish him.