WASHINGTON, Sept. 30 - Federal auditors said on Friday that the Bush administration violated the law by buying favorable news coverage of President Bush's education policies, by making payments to the conservative commentator Armstrong Williams and by hiring a public relations company to analyze media perceptions of the Republican Party.

In a blistering report, the investigators, from the Government Accountability Office, said the administration had disseminated "covert propaganda" in the United States, in violation of a statutory ban.

The contract with Mr. Williams and the general contours of the public relations campaign had been known for months. The report Friday provided the first definitive ruling on the legality of the activities.

Lawyers from the accountability office, an independent nonpartisan arm of Congress, found that the administration systematically analyzed news articles to see if they carried the message, "The Bush administration/the G.O.P. is committed to education."

The auditors declared: "We see no use for such information except for partisan political purposes. Engaging in a purely political activity such as this is not a proper use of appropriated funds."

The report also sharply criticized the Education Department for telling Ketchum Inc., a public relations company, to pay Mr. Williams for newspaper columns and television appearances praising Mr. Bush's education initiative, the No Child Left Behind Act.