WASHINGTON -- Former Deputy Interior Secretary J. Steven Griles has pleaded guilty to obstruction of justice in a Senate committee's investigation.

Griles becomes the highest-ranking Bush administration official convicted in the Jack Abramoff corruption scandal.

President George W. Bush nominated Griles as deputy to Interior Secretary Gale Norton, a former Colorado attorney general who was interior secretary from 2001 to 2006.

Griles has admitted in federal court that he lied to the Senate about his relationship with Abramoff, who repeatedly sought Griles' intervention at the agency on behalf of Abramoff's Indian tribal clients.

Democrats were quick to seize on the plea.

"No matter how far they fall or how many end up in jail, the Bush Republicans just can't kick their addiction to their culture of corruption," said Democratic National Committee Communications Director Karen Finney.

Assistant Attorney General Alice Fisher said the case shows the Justice Department is willing to go after "public corruption at all levels of government."

Federal prosecutors said they are seeking no more than a 10-month prison sentence for Griles.