Updated

President Obama and his national security team are appealing to lawmakers for last-minute changes to a sweeping defense bill that mandates military custody for terrorism suspects linked to Al Qaeda, including those captured within the U.S.

The legislation is caught in an escalating dispute between the White House and Congress over the politically charged issue of whether to treat suspected terrorists as prisoners of war or criminals.

The president led a full-court press this week that included Secretary of State Hillary Rodham Clinton, Defense Secretary Leon Panetta and FBI Director Robert Mueller asking for revisions to the bill as House and Senate negotiators move swiftly to complete a final version. The White House already had threatened a veto if the bill isn't changed, saying it could not accept legislation that "challenges or constrains the president's authorities to collect intelligence, incapacitate dangerous terrorists and protect the nation."

Obama spoke to Senate Armed Services Committee Chairman Carl Levin, D-Mich. Clinton and Panetta also spoke to Levin, and Mueller has met with Republican Sens. John McCain of Arizona, Lindsey Graham of South Carolina and Kelly Ayotte of New Hampshire, administration and congressional officials said Friday.

They spoke on condition of anonymity to discuss private conversations.

The administration insists that the military, law enforcement and intelligence agents need flexibility in prosecuting the war on terror. Obama points to his administration's successes in eliminating Osama bin Laden and Al Qaeda figure Anwar al-Awlaki. Republicans counter that their efforts are necessary to respond to an evolving, post-Sept. 11 threat, and that Obama has failed to produce a consistent policy on handling terror suspects.

The Senate bill would require that the military take custody of a suspect deemed to be a member of Al Qaeda or its affiliates and involved in plotting or committing attacks on the United States, with an exemption for U.S. citizens. The bill does allow the executive branch to waive the military's authority based on national security and hold a suspect in civilian custody, but the administration argues that is insufficient.

"We want to work with the Senate to ensure our counterterrorism professionals have the tools and flexibility they need to keep America safe," National Security Council spokesman Tommy Vietor said Friday.

As negotiators have raced to finish the bill, administration officials have offered various changes to the provisions but have had little success in persuading lawmakers. One potential change was to limit the cases in which the military custody provision would apply.

The legislation also would deny suspected terrorists, even U.S. citizens seized within the nation's borders, the right to trial and subject them to indefinite detention.

The Obama administration also opposes that change.

The administration also is seeking changes to potential sanctions on Iran, penalties that the Senate passed on a 100-0 vote last week.

The bill would go after foreign financial institutions that do business with Iran's central bank by barring them from opening or maintaining correspondent operations in the United States. It would apply to foreign central banks only for transactions that involve the sale or purchase of petroleum or petroleum products.

The petroleum penalties would only apply if the president, in six months, determines there is a sufficient alternative supply and if the country with jurisdiction over the financial institution has not significantly reduced its purchases of Iranian oil. It also allows the president to waive the penalties based on national security.

Treasury Secretary Timothy Geithner, in a Dec. 1 letter to senators, said the administration opposed the measure in its current form because it would undermine its effort to bring international pressure on Iran. He also warned that the penalties could actually boost oil prices and benefit Iran financially.

"Iran's greatest economic resource is its oil exports," Geithner wrote. "Sales of crude oil line the regime's pockets, sustain its human rights abuses and feed its nuclear ambitions like no other sector of the Iranian economy."

The administration is seeking both substantive and technical changes, including delaying implementation of all the penalties for six months.

Overall, the bill would authorize $662 billion for military personnel, weapons systems, national security programs in the Energy Department, and the wars in Iraq and Afghanistan in the fiscal year that began Oct. 1. Reflecting a period of austerity and a winding down of decade-old conflicts, the bill is $27 billion less than Obama requested and $43 billion less than Congress gave the Pentagon for the year before.