U.S. President Barack Obama and former Republican rival Mitt Romney met for a private lunch at the White House on Thursday, their first meeting since the Nov. 6 election, fulfilling a promise Obama made in his victory speech.

Romney left after just over an hour.

CBC's Susan Bonner said the meeting was held in in the president's private dining room. Reporters were not even permitted to capture an image of the two men together, she said from Washington, "which makes what really happened at the lunch all that much more interesting."

White House spokesman Jay Carney said the president and Romney wanted to keep the meeting private.

Meeting standard in modern American politics

This type of meeting between the elected president and his main competitor in the election has become a standard political gesture in modern American politics, Bonner said.

"It’s not like Canada where the winner and the loser after an election face off against each other, again and again… in the House of Commons."

Romney, who lost the presidential election despite a surge toward the end of the campaign, has no official role in Washington.

Carney said Obama had no specific agenda for the meeting, but he said the president wanted to discuss Romney's ideas for making government more efficient. Obama has proposed merging some functions of government related to business and has asked Congress for authority to undertake some executive branch reorganization.

"The president noted that Gov. Romney did a terrific job running the Olympics and that that skills set lends itself to ideas that could make the federal government work better, which is a passion of the president's," Carney said.

Romney adviser Eric Fehrnstrom called it a "very friendly lunch. They spoke about some of the big challenges facing America, and it gave Gov. Romney the opportunity to personally congratulate President Obama for the success of his campaign."

Man arrested after interfering with Romney's motorcade

The U.S. Secret Service said a man interfered with Romney's motorcade as his vehicle arrived at a secure checkpoint near the White House. The man was later arrested after he became combative during an interview with a police officer.

Secret Service spokesman Max Milien said the man, who was not identified, was standing near a security entrance to the White House and got in the motorcade's way. The vehicle stopped briefly at the security gate and then entered the White House complex.

Milien said the man was later interviewed by an officer and became combative. He was charged with assault on a police officer and unlawful entry.

A CNN video of the incident shows a man briefly heckling Romney near the passenger side of the sport utility vehicle before it proceeded through the gates and onto the grounds of the White House.

Romney and Ryan talk U.S. economy

Obama and Romney's meeting was thought to be their most extensive private talk to date. They had only a handful of brief exchanges before the 2012 election, and their campaign interactions were largely confined to the three presidential debates.

Obama aides said they reached out to Romney's team shortly before the Thanksgiving holiday last week to start working on a date for the meeting.

For Romney, it was a day of closure after a hard-fought campaign.

Romney and Representative Paul Ryan, his former running mate, met earlier in the day to talk about economic challenges facing Washington, a Ryan aide said. The person spoke on the condition of anonymity because the aide was not authorized to discuss the private discussions.

Much of the economic debate centres on expiring tax cuts first enacted in the George W. Bush administration. Obama and Romney differed sharply during the campaign over what to do with the cuts, with the Republican pushing for them to be extended for all income earners, and the president running on a pledge to let the cuts expire for families making more than $250,000 US a year.

The White House sees Obama's victory as a signal that Americans support his tax proposals.

Romney has virtually disappeared from politics following his election loss. He's spent the past three weeks largely in seclusion at his family's California home. He has made no public appearances, drawing media attention only after being photographed at Disneyland in addition to stops at the movies and the gym with his wife, Ann.

With files from CBC News