Bush administration officials broke no laws in withholding from Congress estimates of the cost of the new Medicare law, according to an internal investigation made public yesterday.

The Department of Health and Human Services' inspector general, the agency's internal watchdog, said a three-month investigation found that administration officials had used aggressive tactics to keep from Congress much higher estimates of the legislation's cost -- $100 billion more than what the president and other officials were acknowledging.

But the effort -- including threats by Thomas Scully, the administration's Medicare chief until December, to fire chief Medicare actuary Richard Foster -- did not violate federal law, the inspector general said.

The administrator of the federal Centers for Medicare and Medicaid Services "has the final authority to determine the flow of information to Congress," the unsigned report said.

That conclusion contradicted the findings of the nonpartisan Congressional Research Service, which said in May that the threats against Foster, designed to keep him from giving Democratic lawmakers his projections of the bill's cost, probably broke the law. The Justice Department, in an opinion attached to yesterday's report, said the CRS was wrong.

The General Accounting Office, Congress's investigative arm, is also looking into whether the gag order violated federal law.

Democrats said the inspector general's inquiry was narrowly tailored, underscoring the need for an independent investigation that would also look at whatever role the White House played in the suppression of information.

"It sounds as though the Bush administration examined itself and found it did nothing wrong," said Rep. Fortney "Pete" Stark (Calif.), senior Democrat on the House Ways and Means subcommittee on health.

Dara Corrigan, the acting HHS inspector general, said her office is continuing to investigate the ethics waiver that HHS Secretary Tommy G. Thompson granted Scully, allowing him to continue to work on Medicare legislation while he was looking for work with law and investment firms that have clients who would be affected by the legislation.