By David Alexander

WASHINGTON (Reuters) - President Barack Obama threatened on Tuesday to veto a defense policy bill in the House of Representatives that would authorize higher Pentagon spending and tie his hands on national security issues from nuclear arms reductions to handling war detainees.

In a move that set the White House on a collision course with lawmakers in the Republican-led House, the administration warned that the National Defense Authorization Act being debated by the House this week hampers the Pentagon's new defense strategy and infringes on the president's powers as commander.

"If the cumulative effects of the bill impede the ability of the administration to execute the new defense strategy and to properly direct scarce resources, the president's senior advisers would recommend ... that he veto the bill," the White House said in a statement of administration policy.

It was the second time in less than a week that the administration has expressed displeasure over provisions of the measure, which would add nearly $4 billion to Obama's defense-spending request and undo many of the cuts the Pentagon proposed in an effort to meet cost-reduction targets set by Congress.

Defense Secretary Leon Panetta warned at a news conference last Thursday that the House was courting gridlock by trying to increase defense spending to about $554 billion while slashing social programs for the poor and needy in an effort to prevent a new round of defense cuts.

Representative Buck McKeon, head of the House Armed Services Committee, responded sharply in a letter, saying Panetta himself had said that efforts to trim $487 billion from projected Pentagon spending over the next decade had taken the Defense Department "right to the razor's edge."

The Defense Department was directed to make the spending cuts as part of the administration's efforts bring its trillion-dollar budget deficit under control. The Pentagon will be hit by another $500 billion in cuts over the next decade beginning in January unless Congress acts to avert them.

APPROPRIATING FUNDS

The White House statement listed a series of objections to the authorization act, a policy bill that sets spending levels but does not actually appropriate funds. The measure is due to be debated by the full House this week but would have to be passed by the Senate before it could go to Obama for signature.

The White House strongly objected to sections in the bill that could block implementation of parts of the New START nuclear arms reduction treaty with Russia.

The measure stops arms reductions under New START unless the administration abides by its pledges to fund the revitalization of the United States' nuclear infrastructure. Some officials say the pace and timing of spending agreed during the passage of the treaty are no longer appropriate.

The administration also objected to provisions in the bill dealing with handling of detainees in the war against al Qaeda insurgents and their allies.

The administration has repeatedly clashed over the issue with Congress, which prevented the administration from sending detainees to the United States for trial.

The White House also objected to a series of moves by the House that would undo many of the cuts proposed by the Pentagon as part of its efforts to reduce spending.

The measure seeks to slow the pace of Pentagon troop reductions to no more than 15,000 soldiers and 5,000 Marines per year between 2014 and 2017. The Pentagon plans to reduce the size of the force by a total 72,000 soldiers and 20,000 Marines.

The House bill also tries to block Pentagon plans to eliminate or retire several types of cargo aircraft, as well as a variant of the Global Hawk surveillance drone. It also seeks to restrict retirements of ballistic missile submarines.

(Editing by Philip Barbara)