WASHINGTON (AP) — A top White House adviser insisted Sunday that President Barack Obama learned the Internal Revenue Service had targeted tea party groups only "when it came out in the news" while Republicans continued to press the administration for more answers.

Trying to move past a challenging week that put the White House on the defensive, senior adviser Dan Pfeiffer was scheduled to appear on five Sunday news shows to repeat the administration's position that no senior officials were involved in the decision to give tea party groups extra scrutiny. Pfeiffer's appearances were unlike to quiet GOP critics, who have seized on the revelations as proof that Obama used the IRS to go after his political enemies.

"The deputy secretary of the treasury was made aware of just the fact that the investigation was beginning last year," Pfeiffer said. "But no one in the White House was aware."

Meanwhile, Sen. Rand Paul, R-Ky., suggested there was a written policy to target conservative groups opposing the president, but when pressed could not provide details.

"I haven't seen a policy statement, but I think we need to see that," Paul said. "And when that comes forward, we need to know who wrote the policy and who approved the policy."

Regardless of when the president first learned of the investigations, Pfeiffer said the president wanted to ensure such activities were not repeated.

"The activity was outrageous and inexcusable, and it was stopped and it needs to be fixed to ensure it never happens again," Pfeiffer said.

A Treasury Department inspector's report said this week that conservative and small-government tea party groups that were critical of Obama received extra scrutiny. IRS agents did not flag similar progressive or liberal groups, according to the watchdog.

The report concluded that a regional IRS office in Ohio improperly singled out tea party and other conservative groups for more than 18 months and took no action on many of their applications for tax-exempt status for long periods of time — hindering their fundraising for the 2010 and 2012 elections.

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The new acting IRS commissioner is in the midst of a 30-day top-to-bottom review while Republicans continue to demand answers of Obama and his allies in government.

That's not sufficient, said Sen. Rob Portman, R-Ohio.

"I think a special counsel is going to wind up being necessary," he added said.

That move is not needed, said Sen. Robert Menendez, D-N.J.

"I don't see the point," he said of a special counsel to investigate the scandal.

Rep. Tom Price, R-Ga., said the IRS had stepped so far over its mandate that it asked book groups for reading lists and church groups about their prayers before granting them tax-exempt standing. It's government over-reach, he said, and a reason why Republicans need to have their own investigation into the agency.

"This is about trust," Price said.

But he stopped short of calling for a special counsel.

Rep. Charlie Rangel, D-N.Y., said Republicans were using the incidents to embarrass the president.

"There is no Republican agenda other than to stop the president of the United States," he said.

Pfeiffer was appearing Sunday on ABC's "This Week," NBC's "Meet the Press," CBS' "Face the Nation," CNN's "State of the Union" and "Fox News Sunday." Portman, Menendez, Price and Rangel were on ABC. Paul was on CNN.