Newt Gingrich appears at a town hall in West Columbia on January 17, 2012. (Getty Images)
Washington, DC (by Catalina Camia & Jackie Kucinich/USA Today) -- Newt Gingrich reportedly will end his presidential campaign next Tuesday, according to reports by CNN and Fox News.
Sources close to Gingrich told the networks that the former House speaker will formally endorse Mitt Romney and end his White House bid.
Earlier this morning, Gingrich told a North Carolina audience that he's "working out the details of our transition."
CNN's PoliticalTicker blog said Gingrich frequently referred to himself as a"citizen" at the North Carolina event and said "it's pretty clear that Gov. Romney is going to be the nominee."
Romney swept five states in primaries last night and declared the nomination battle over. In his remarks Tuesday night, Gingrich said he would look "realistically" at the state of his campaign, which is mired in debt and is well out of reach of attaining the 1,144 delegates needed for the nomination.
Gingrich told his North Carolina audience that he is "committed" to the Republican Party and to helping defeat President Obama in November.
Gingrich's campaign has been gasping for air for weeks. Last month, he laid off a third of his staff and cut back on his travel schedule, in a bid to engage voters through social media.
He recently campaigned heavily in Delaware, but lost last night's primary there to Romney by 30 percentage points.
The former House speaker -- credited with bringing Republicans into the House majority in the 1990s after four decades in the political wilderness -- had been declared dead more than once in the presidential campaign.
The first time occurred just days after Gingrich formally announced his candidacy last May, when he referred to the House Republican budget plan as "right wing social engineering."
The gaffe, which he quickly took back, was followed by a mass exodus of his staff following a disagreement over the "vision" for the campaign.
But then Gingrich saw his popularity rise and his campaign coffers fill up after a series of strong performances in GOP debates -- a trend that culminated with his win of South Carolina's primary. Romney battled back and had a decisive win in Florida, and Gingrich's momentum then faded quickly.
In the past three months, Gingrich has only won his home state of Georgia.
Gingrich at times complained bitterly about attack ads and campaign spending by Romney and his allies. Romney and the Restore Our Future super PAC portrayed Gingrich as unfit to lead, bringing up such things as the former House speaker's work for mortgage giant Freddie Mac and appearing in a climate change ad with House Democratic leader Nancy Pelosi.
Before Tuesday night's five primaries, The Washington Post noted Gingrich finished 4th in 16 of the 30 states he had competed in.