WASHINGTON: President Barack Obama overruled two senior government lawyers in deciding that he had the authority to continue U.S. military operations in Libya without Congressional approval, The New York Times reported late Friday.

In reaching his conclusion Obama rejected the opinions of Jeh Johnson, the Pentagon general counsel, and Caroline Krass, the acting head of the Justice Department's Office of Legal Counsel, The Times reported, citing unnamed officials familiar with the deliberations.

Johnson and Krass both told the White House they believed that U.S. military activity in the NATO-led air war over Libya amounted to "hostilities."

Under the 1973 War Powers Resolution (WPR), a president has 60 days to get authorization from Congress – which under the U.S. constitution has the authority to declare war – for a military deployment. Failing that, the Resolution sets a further 30 days to withdraw U.S. forces from harm's way.

Obama however agreed with two other top government lawyers – White House counsel Robert Bauer and State Department legal adviser Harold Koh – who said the U.S. military action in Libya did not amount to "hostilities" because it was in a support role.

The White House said it would not comment on the Times report, but spokesman Eric Schultz described the deliberations as "a robust process."

The WPR "has been subject to intense debate since it was first enacted in 1973, and even critics of the administration's position concede the legitimacy of different points of view," said Schultz, adding that "there was a full airing of views within the administration."

He said the White House would not discuss the internal process in which Obama receives legal advice, but said: "It should come as no surprise that there would be some disagreements, even within an administration, regarding the application of a statute that is nearly 40 years old to a unique and evolving conflict."

Reports of internal disagreements, despite being downplayed by the White House, are certain to fuel the building political row in Washington over the U.S. role in NATO's Libya mission, and claims in Congress that the president overstepped his powers in ordering the conflict.

That Obama is reported to have overruled a top Pentagon lawyer will also likely add to speculation of differences of approach on some national security issues between the White House and the Defense Department – key figures including Defense Secretary Robert Gates were seen as skeptical of U.S. intervention in Libya from the outset.

The White House on Wednesday made their case for participating in the NATO-led assault on Moammar Gadhafi's forces in a 30-page report to lawmakers.

The document was compiled after Republican House Speaker John Boehner sent a scathing letter to the president warning that U.S. operations would be illegal come Sunday because they lacked formal congressional approval.

"U.S. forces are playing a constrained and supporting role in a multinational coalition," the White House report said, noting that the use of force was being used solely to protect civilians, enforce a no-fly zone and an arms embargo.

A senior administration official added: "we are not engaged in any of the activities that typically over the years in war powers analysis has been considered to constitute hostilities within the meaning of the statute."