WASHINGTON -- The Internal Revenue Service asked “unnecessary, burdensome questions” of conservative groups seeking tax-exempt status, questions that unfairly delayed the applications, according to an investigative report obtained Tuesday by McClatchy.

Ultimately, the organizations were told the information was not needed, according to the report by the Treasury inspector general for tax administration. The report, which has not yet officially been made public, has fueled allegations of abuse of government power to target the rising tea party political movement.

“The report’s findings are intolerable and inexcusable,” President Barack Obama said in a statement Tuesday evening after reading the report.

“The federal government must conduct itself in a way that’s worthy of the public’s trust, and that’s especially true for the IRS. The IRS must apply the law in a fair and impartial way, and its employees must act with utmost integrity. This report shows that some of its employees failed that test.”

He said he directed Treasury Secretary Jack Lew “to hold those responsible for these failures accountable, and to make sure that each of the Inspector General’s recommendations are implemented quickly, so that such conduct never happens again.”

While the report from Inspector General J. Russell George gave no indication that he encountered legal violations in his audit, Attorney General Eric Holder said Tuesday that he’s ordered a criminal investigation of the IRS actions.

“The FBI is coordinating with the Justice Department to see if any laws were broken in connection with those matters related to the IRS,” Holder told reporters. “Those were, I think as everyone can agree, if not criminal, they were certainly outrageous and unacceptable.”

At the same time, pressure mounted on the Obama administration Tuesday to disclose who in the White House knew about the actions by the IRS. The inspector general’s report said it found no evidence of influences from outside the IRS.

“Unfortunately, the report raises more questions than it answers,” said House Oversight Committee Chairman Rep. Darrell Issa, R-Calif.

“What we do know for sure is that the IRS personnel responsible for granting tax exemptions systematically targeted conservative groups for extra scrutiny, and that officials in Washington, D.C., were aware of this practice, even while publicly claiming that it never happened,” Issa said.

Leaked portions of the report emerged Monday and sparked a firestorm in the nation’s capital. The leaks suggested that top IRS officials, including current acting chief Steven Miller, were aware of the unusual targeting of conservative groups as far back as at least May 2012. Lower level officials knew about it at least since April 2010.

The full report obtained Tuesday concluded that the Cincinnati-based Determinations Unit developed and used inappropriate criteria that effectively slowed down applications when an organization had tea party or other political names. It said the IRS agreed with most but not all of the unit’s recommendations.

“Although the IRS has taken some action, it will need to do more so that the public has reasonable assurance that applications are processed without unreasonable delay in a fair and impartial manner in the future,” the report said.