By David Alexander

WASHINGTON (Reuters) - The Obama administration sharply criticized a $649 billion defense spending bill in the Republican-controlled House of Representatives on Thursday because of proposed spending cuts and limits on the handling of Guantanamo detainees.

"The administration strongly opposes a number of provisions in this bill," the White House said in a policy statement. "If a bill is presented to the president that undermines his ability as commander-in-chief or includes ideological or political policy riders, the president's senior advisers would recommend a veto."

The White House raised its concerns as the full House of Representatives prepared to debate a defense appropriations bill that would set levels for most military spending for the 2012 fiscal year beginning in October.

The bill, which was taken up by the House on Thursday evening, was expected to face a large number of amendments, including a move to halt U.S. participation in the NATO-led campaign against Libyan leader Muammar Gaddafi by barring any spending on the effort.

With President Barack Obama struggling to cut the nation's $1.4 trillion deficit and $14 trillion debt, war-weary lawmakers facing cuts to social programs are pressing the administration for greater reductions in defense spending. The current House measure cuts Obama's spending request by $8.9 billion.

"Our nation needs a lean and powerful and effective military," Representative Alcee Hastings said in the House on Thursday. "We also have great needs in this country and we cannot continue to slash funding for essential programs here at home in favor of ever increasing funding for wars abroad."

The appropriations bill is a long way from final passage. The Senate's version of the bill is still in committee. Whatever version is ultimately passed by the House would have to be reconciled with a bill adopted by the Democratic-led Senate before it would go to Obama for his signature.

GUANTANAMO

The White House expressed particular concern with House efforts to place restrictions on how it handles terrorism terrorists held at the U.S. military prison at Guantanamo Bay, Cuba.

The House bill would prevent the transfer of self-proclaimed September 11 mastermind Khalid Sheikh Mohammed and any other foreign terrorism suspect to the United States, effectively preventing them from facing U.S. trial or imprisonment.

That language "is a dangerous and extraordinary challenge to the critical executive branch authority to determine when and where to prosecute detainees, based on the facts and the circumstances of each case and national security interests," the White House statement said.

"It unnecessarily constrains the nation's counterterrorism efforts and would undermine national security, particularly where federal courts are the best -- or even the only -- option for incapacitating dangerous terrorists," it said.

The measure is part of a long-running struggle between Obama and some lawmakers over whether terrorism suspects should be prosecuted as enemy combatants before military commissions or as criminal suspects in federal courts.

In April, the administration abandoned a two-year effort to prosecute Mohammed and four suspected September 11 co-conspirators in a federal court. Attorney General Eric Holder said lawmakers had "tied our hands" by blocking funding for the move in 2011.

The White House also objected to series of cuts the House made in its spending request, including a reduction in funding for the Defense Advanced Research Projects Agency that it said would "undermine the nation's ability to invest in innovation and ideas" important for national security.

(Editing by Peter Cooney)