Citing officials familiar with the administration’s deliberations, the newspaper reported the Pentagon and Justice Department lawyers argued that the US bombing runs over Libya, under NATO command, were “hostilities.”

As such, Obama would have had to end or pull back the military flights after May 20 since he did not get backing from Congress for them under the War Powers Resolution.

The Times reported that Obama instead latched onto legal advice from inside the White House and the State Department that the bombing missions fell short of “hostilities” and that they could continue without the green light from Congress.

Among those reported to support the president’s action were White House counsel Robert Bauer and State Department legal adviser Harold H. Koh, the paper said. Those opposed included Pentagon General Counsel Jeh C. Johnson and acting head of the Justice Department’s Office of Legal Counsel Caroline D. Krass.

One issue was reported to be whether firing missiles from drones amounted to hostilities.

House of Representatives Speaker John Boehner, the top Republican in Congress, is pressuring the White House to detail the advice the Justice Department Office of Legal Counsel provided on the legality of continuing US military activity against Libya, which is officially aimed at shielding civilians there from the forces of Libyan leader Muammar Qaddafi.

The Times story noted that it is rare for a president to override the legal opinions provided by that office.

The White House has acknowledged differences of opinion within the administration on the legal question.

It has maintained that US military activity against Libya is limited, without any plans to commit ground troops. Democrats in Congress, including Senate Majority Leader Harry Reid, have backed Obama’s refusal to invoke the War Powers Act and have suggested the Libya mission is likely to end soon.

The 1973 War Powers Resolution was passed during the era of the Vietnam War to set out the powers of the president and Congress regarding US military actions. It prohibits US armed forces from being involved in military actions for more than 60 days without congressional authorization.

White House spokesman Jay Carney addressed the internal debate over the resolution at his briefing Thursday.

He said “there was a robust process through which the president received the advice he relied on in determining the application” of the War Powers Resolution.

He noted the resolution has been subject to intense debate since it was first enacted in 1973.

“We are not going to get into the internal process by which the president receives legal advice,” Carney said.

“It should come as no surprise that there would be some disagreements, even within an administration, regarding the application of a statute that.