WASHINGTON - Republicans and Democrats on Thursday derided President Barack Obama's claim that US air attacks against Libya do not constitute hostilities and demanded that the commander in chief seek congressional approval for the 3-month-old military operation.

In an escalating US constitutional fight, the Republican leader of the House of Representatives threatened to withhold money for the mission, pitting a Congress eager to exercise its power of the purse against a dug-in White House. Speaker John Boehner signaled that the House could take action as early as next week.

"The accumulated consequence of all this delay, confusion and obfuscation has been a wholesale revolt in Congress against the administration's policy," said Sen. John McCain, the top Republican on the Armed Services Committee who has backed Obama's actions against Libya.

The administration, in a report it reluctantly gave to Congress on Wednesday, said that because the United States is in a supporting role in the NATO-led mission, American forces are not facing the hostilities that would require the president to seek such congressional consent under the War Powers Resolution.

The 1973 law prohibits the military from being involved in actions for more than 60 days without congressional authorization, plus a 30-day extension. The 60-day deadline passed last month with the White House saying it is in compliance with the law. The 90-day mark is Sunday.

In the meantime, Libyan leader Moammar Gadhafi has maintained his grip on power, and the White House says if the mission continues until September, it will cost $1.1 billion.

Instead of calming lawmakers, the White House report and its claims about no hostilities further inflamed the fierce balance-of-power fight between the legislative and executive branches.

"We have got drone attacks under way, we're spending $10 million a day. We're part of an effort to drop bombs on Gadhafi's compound. It doesn't pass the straight-face test, in my view, that we're not in the midst of hostilities," Boehner told reporters at a news conference.

Sen. Jim Webb, a Democrat, combat veteran and member of the Armed Services Committee, scoffed at the notion.

"Spending a billion dollars and dropping bombs on people sounds like hostilities to me," Webb said in an interview.

Sen. Bob Corker, a Republican, called the claims "really totally bizarre." Rep. Tom Rooney, a Republican, said telling Congress and Americans "that this is not a war insults our intelligence. I won't stand for it and neither will my constituents."

The White House pushed back, singling out Boehner and saying he has not always demanded that presidents abide by the War Powers Resolution.

White House spokesman Jay Carney said Boehner's views "stand in contrast to the views he expressed in 1999 when he called the War Powers Act 'constitutionally suspect' and warned Congress to 'resist the temptation to take any action that would do further damage to the institution of the presidency."

Boehner's spokesman, Brendan Buck, dismissed Carney's reference to a "decade-old statement."

"As speaker, it is Boehner's responsibility to see that the law is followed, whether or not he agrees with it," Buck said.

The White House response has complicated efforts for several Democrats and Republicans urging their colleagues to hold off on any action that could encourage Gadhafi. In a Senate speech, McCain said it would be a mistake for the United States to cut and run from its allies and the mission.

Speaking directly to Republicans, McCain asked, "Is this the time to ride to the rescue of the man who President Reagan called the mad dog of the Middle East?"

McCain said later that he and Senate Foreign Relations Committee Chairman John Kerry, a Democrat, would push ahead with a resolution authorizing the US mission in Libya with conditions. The committee twice postponed meetings to finalize the resolution.

"The convoluted definition of hostilities backs us into a corner," said Sen. Lindsey Graham, a Republican.

In a letter to Obama this week. Boehner said the commander in chief will clearly be in violation of the War Powers Resolution on Sunday and he pressed the administration to state the legal grounds for Obama's actions. The House speaker said Thursday the White House report failed to answer his questions and that he expects a response by his Friday deadline.

Previous presidents, Republicans and Democrats, have largely ignored the Vietnam-era law, which was created as a check on their power to authorize military force.

Countering the criticism, House Democratic leader Nancy Pelosi of California said Obama did not need congressional authorization, but she acknowledged the congressional frustration.

"It's like a marriage. You may think you're communicating, but if the other party doesn't think you're communicating, you're not communicating enough," Pelosi told reporters.

The White House sent Congress the 32-page report in response to a nonbinding House resolution passed this month that chastised Obama for failing to provide a "compelling rationale" for US involvement in Libya.

The administration report estimated the cost of US military operations at about $715 million as of June 3, with the total increasing to $1.1 billion by early September.

While the US led the initial airstrikes on Libya, NATO forces have since taken over the mission. The U.S still plays a significant support role that includes aerial refueling of warplanes and intelligence, surveillance and reconnaissance work. Obama has ruled out sending US ground forces to Libya.