Republican candidate Greg Gianforte used his victory speech after winning the Montana special election on Thursday to apologize for body-slamming a Guardian journalist the day before.

Within minutes of being declared the winner, Gianforte appeared on stage at his campaign headquarters in Bozeman, Montana, with his wife Susan.

Between chants of 'drain the swamp' from his gathered supporters, he found a moment to apologize to reporter Ben Jacobs who he 'body-slammed' the previous day.

'Last night, I made a mistake and I took an action that I can't take back and I'm not proud of what happened.

'I should not have responded in the way that I did...I should not have treated that reporter that way and for that I am sorry, Mr Ben Jacobs,' he said.

It was a marked change from the campaign statement he issued on Wednesday which blamed the scuffle on 'liberal journalist' Jacobs and came after calls from House Speaker Paul Ryan who implored him to apologize.

Gianforte won the election with 50.4 percent of the vote over his Democrat opponent Rob Quist's 43.9.

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'I'm sorry': Greg Gianforte apologized for body-slamming a Guardian journalist as he delivered his victory speech after winning the Montana special election on Thursday night in Bozeman

The 56-year-old was joined on stage to celebrate the victory with his wife Susan

As he launched in to his apology, the newest Representative-elect was forced to silence laughs from the crowd.

'Last night, I learned a lesson.

MONTANA SPECIAL ELECTION RESULTS Greg Gianforte (R) 189,473 (50.2%) Rob Quist (D) 166,483 (44.1%) Mark Wicks (Libertarian) 21,509 (5.7%) Source: AXIOS Advertisement

'No, please. I need to share something from my heart here and I ask you to bear with me. When you make a mistake you have to own up to it. That's the Montana way,' he said.

He also apologized to others who witnessed the incident with Jacobs, including a Fox News crew which contradicted his initial version of events by telling police that he grabbed Jacobs by the neck with both hands.

'I'm sorry to each one of you, that we had to go through this.

'That's not the person that I am and it's not the way I'll lead in this state,' he said.

Gianforte's supporters laughed as he addressed the incident and shouted: 'We forgive you!' as he made his apology.

His victory speech was his first appearance since he assaulted Jacobs at his campaign headquarters on Wednesday afternoon.

Jacobs tried to approach him to ask a question about healthcare when he was slammed to the ground.

Susan Gianforte offered a wide smile as she celebrated with her husband on Thursday night

Greg Gianforte gives his victory speech at his campaign headquarters in Bozeman, Montana

Gianforte's appearance at his victory party was his first outing since the incident on Wednesday

The newly named Representative-elect vowed to put 'Montana first again', borrowing lines from President Trump's campaign as he delivered his speech

Gianforte was charged with assault on Thursday night after 'body-slamming' Guardian reporter Ben Jacobs. The incident gained traction when Jacobs tweeted about it

He recorded the incident on his iPhone which was primed to record the candidate's words.

In the recording, Gianforte can be heard screaming: 'Get the hell outta here!' after knocking the journalist to the ground.

Jacobs, incredulous, replied: 'You just broke my glasses!'

Jacobs was taken to hospital after the incident

The candidate's media spokesman tried to play down the incident, issuing a statement on Wednesday night to say the reporter had been 'aggressive' and claiming the pair fell to the ground together.

'Tonight, as Greg was giving a separate interview in a private office, The Guardian's Ben Jacobs entered the office without permission, aggressively shoved a recorder in Greg's face and began asking badgering questions,' a campaign statement read.

'Jacobs was asked to leave. After asking Jacobs to lower the recorder, Jacobs declined. Greg then attempted to grab the phone that was pushed in his face.

'Jacobs grabbed Greg's wrist and spun away from Greg, pushing them both to the ground.'

'It's unfortunate that this aggressive behavior from a liberal journalist created this scene at our campaign volunteer BBQ,' the statement read.

Gianforte won 50.6 percent of the vote while Quist took 43.6 per cent

The Fox News crew discredited it. They described how Gianforte lunged at Jacobs, placing his arms around his neck and throwing him to the ground.

RNC Chairwoman Ronna McDaniel welcomed the apology on Thursday.

'Congressman-elect Greg Gianforte was right to apologize for his actions in Wednesday's incident. Tonight's apology was a good first step toward redemption and I hope Gianforte continues to work toward righting his wrong,' she told ABC.

Officials say more than half of the voting in Thursday's special election had already been done by then by mail, leaving only on-the-day voters to change their minds at the last minute.

In Montana, voters who cast early absentee ballots cannot change them at the last minute unlike in other states.

CNN reported that some voters had attempted to change theirs after Gianforte's altercation.

Elsewhere in his speech, the technology millionaire borrowed campaign favorites from Donald Trump who he said he looked forward to working with.

Despite the scandal on Wednesday, there was a healthy turnout of supporter at Gianforte HQ to watch the results pour in

Republican Daron Olseon celebrates after Greg Gianforte is named the winner of the Montana special election

GREG GIANFORTE'S VICTORY SPEECH 'Thank you, thank you. Thank you Montana. Tonight is all about you. Tonight is your victory. Over the last two years, you've made tens of thousands of phone calls and knocked on hundreds of thousands of doors. Thank you. Susan and I have had the great pleasure of driving over 80,000 miles, through our 56 counties. All over this great state, we stayed in your homes and together tonight we won a victory for our treasured state. Tonight we won a victory for all Montanans. Tonight we won a victory for our coal and timber families. We won a victory for our farmers and our ranchers. And we won a victory for our men and women in uniform and for our veterans. We won a victory for our Montana seniors and we won a victory for our second amendment. We also won a victory to keep our public lands in our public hands. 'We won a victory for every hard working Montana family because their voice hasn't been heard and for Montanans who have been left behind. Tonight, Montanans are sending a wake-up call to the Washington DC establishment. 'Montanans said "Bernie Sanders and Nancy Pelosi don't call the shots here in Montana!" Montanans said "we're gonna drain the swamp". 'We have a lot of work to do and hard work is the way we get things done. And sometimes, hard work is born out of hard lessons. 'Last night, I learned a lesson. No please, I need to share something from my heart here and I ask you to bear with me. When you make a mistake, you have to own up to it. That's the Montana way. 'Last night, I made a mistake and I took an action that I can't take back and I'm not proud of what happened. I should not have responded in the way that I did and I'm sorry for that. 'I should not have treated that reporter that way and for that, I am sorry, Mr. Ben Jacobs. 'I also want to apologize for the Fox News team that was there and I'm sorry to each one of you, that we had to go through this. That's not the person that I am and it's not the way I'll lead in this state. 'Rest assured, our work is just beginning but it does begin with me taking responsibility for my own actions. You deserve a congressman who stays out of the limelight and just gets the job done. 'I promise to work hard to protect our precious way of life. I promise to be open and accessible and based on your input, I'll be your strong voice back in Washington DC. 'I've always considered myself more of a work horse than a show horse and that's my promise to you. I'm going to Washington to get things done, to drain the swamp and fight for Montana families. 'I will bring accountability to Washington DC. I'll support term limits and banning members of congress from becoming lobbyists. 'I'll hold the politicians accountable. If they can't balance a budget, they shouldn't get paid. No balance budget, no pay check. 'Washington won't like it but it's time for America and Montana to come first again. It just seems when people go to DC, they drink the water and slither in to the swamp. 'That's why we're not moving to DC. I'll commute and be back here traveling to every corner of the state as much as I can. I'll be in all 56 counties so that your voice is heard. 'You've always been on my side and I pledge that I'll always be on your side. Montana sent a strong message tonight that we want a congressman that will work with President Trump to make America and Montana great again. I feel a deep sense of obligation and duty to this great state where Susan and I raised our family and built our business. 'Thank you for your support and this opportunity to serve.' Advertisement

During his concession speech, Democratic candidate Rob Quist said: 'I know that Montanans will hold Mr Gianforte accountable'

Quist, a first-time candidate and folk singer, won 43.6 percent of the vote

'Tonight is your victory. Tonight, Montanans are sending a wake up call to the Washington DC establishment.

'Montanans said we're gonna drain the swamp. We have a lot of work to do and hard work is the way we get things done.'

In Missoula, Democrat Rob Quist gave his concession speech after calling Gianforte to congratulate him.

'I know that Montanans will hold Mr. Gianforte accountable,' he said cheerfully, adding to those who were disheartened by the result: 'Don't be discouraged. Be determined.'

There was a healthy turnout at Gianforte's campaign HQ in Bozeman which had been decorated for a win.

A pair of blue cowboy boots were laid next to a podium on the stage in anticipation of his victory speech.

Supporters nervously watched the results pile in and waited for the candidate, who had been laying low since the tape emerged, to make an appearance.

In the recording of his scrap with Jacobs, Gianforte was heard screaming: 'Get the hell outta here!' after taking Jacobs to the ground.

There were jubilant scenes at Gianforte's HQ on Thursday night as the results poured in

Republicans welcomed the results at Gianforte's HQ in Bozeman, Thursday, as he emerged as the winner

Gianforte kept a low profile on Thursday as he recovered from the scandal but the stage was set at his campaign HQ

Supporters kept tabs on the election results at a party for the disgraced candidate

His camp blamed the incident on Jacobs who they said had 'aggressively shoved' his iPhone in front of the candidate's face for an unscheduled interview.

Fox News journalists who witnessed their fight told another story.

They described Gianforte grabbing Jacobs by the neck with both hands and pushing him to the ground.

He earlier tried to dismiss the incident in a statement.

Later in the night, he was cited for misdemeanor assault by Gallantin County Sheriff.

He now has until June 7 to appear before a judge and faces a maximum sentence of six months imprisonment and a $500 fine if convicted.

Gallatin County Attorney Marty Lambert told The Missoulian he plans to review the case to determine why he was charged with a misdemeanor instead of a felony.

The sheriff previously explained his decision, basing it around the fact Jacobs had no visible injuries.

Democrats nervously await the election result at Rob Quist's party in Missoula

Two Quist supporters watch anxiously as the results pour in on Thursday night

The alleged body-slam dominated Thursday's news and permeated Washington DC where House Speaker Paul Ryan called on Gianforte to apologize

The reporter was taken to hospital after the incident and shared a photograph of his broken glasses from inside the ambulance.

On Thursday, he told Good Morning America he was taking 'a lot of Advil' as a result of the scuffle.

The incident on Wednesday prompted a local newspaper to withdraw its endorsement and House Speaker Paul Ryan urged him to apologize for it.

Gianforte is a millionaire hundreds of times over. He made his fortune in technology and sold his customer service software company Rightnow Technology to Oracle for $1.8billion in 2012.

He is a California native but has lived in Montana for years with his wife and family and ran unsuccessfully to become Governor of the state in 2016.

Quist, by contrast, is a first time candidate and folk singer. While Gianforte kept a low profile on Thursday, Quist used his final hours of campaigning trying to squeeze some advantage out of his opponent's embarrassment the night before.

Gianforte replaces Ryan Zinke who elevated from the house to become Secretary of the US Department of the Interior in March, leaving Montana's seat open.

The scandal didn't appear to have too drastic an effect in Montana, however, where most of the voting had already been done by mail