Steven Woolfe has been discharged from hospital after an altercation with a fellow Ukip MEP.
The North West England representative has claimed his colleague Mike Hookem “came at him” in a scuffle outside a meeting in Strasbourg.
Mr Woolfe was taken to hospital with a suspected head injury after suffering from seizures and collapsing later that day.
A party spokesman said: “Steven Woolfe has today been discharged from hospital in Strasbourg. He is focused on continuing his recovery and will not be making any further statements today.”
Mr Hookem has denied punching Mr Woolfe and posted a photograph of his hands on Twitter.
An internal Ukip probe is to investigate the incident, with some senior figures saying it should bar leadership front-runner Mr Woolfe from continuing in the race to head the party.
Meanwhile, medical examinations suggest Mr Woolfe has bruising on his face not consistent with just a fall or seizure, the Ukip MEP has revealed.
The news will intensify controversy that has engulfed Ukip since the Mr Woolfe was taken to hospital after an altercation with fellow MEP Mr Hookem.
A spokesman for Mr Woolfe said: “A team of experts independent of the hospital staff were called in to examine physical injuries to Steven’s face, head and body that were inconsistent with just a seizure, or a fall as a result of a seizure.
“The team of experts also examined other pieces of evidence including clothing and images relating to those injuries.
“Their report will shine a different light on claims currently being made in the media.”
Mr Hookem, of Hull, has insisted he did not punch Mr Woolfe, and told The Yorkshire Post the incident amounted to “handbags at dawn”.
Mr Hookem said he standing by his version of events and seeking legal advice, according to Sky News.
The MEP said reports that he punched the MEP were incorrect. He told the Press Association: “That’s totally wrong. I never touched him, never hit him, never punched him, never slapped him or anything else I’ve been accused of doing.”
After a disagreement over the reasons for Mr Woolfe being barred from the last leadership contest, Mr Hookem said his colleague told him: “Well if that’s the tone of this meeting, maybe me and you should take it outside the room, mano-a-mano.”
He said Mr Woolfe then picked up his jacket and went out of the room.
“So I went out of the room into this small anteroom where he came at me. And what occurred was a tussle. Nothing happened. It was literally seconds because the other MEPs followed us in there.
“The door opened. I backed off. Steven fell through the door and I went back to sit back down again.”
His account is at odds with North West England MEP Mr Woolfe, who told the Daily Mail Mr Hookem “came at me and landed a blow” and that he fell back and hit the door frame.
The latest twist to the saga came as MEP Roger Helmer said a “black mark” will be put over Mr Woolfe’s standing for the leadership of Ukip if a party probe rules he intentionally started a fight.
Roger Helmer insisted questions would be raised over Mr Woolfe’s fitness for the party’s top job if it is found he instigated the “altercation” with Mr Hookem.
The intervention came after senior party figures suggested Mr Woolfe’s apparent willingness to resort to violence made him unsuitable for leadership.
Mr Helmer said an internal Ukip investigation into the tussle between the two MEPs would be crucial to Mr Woolfe’s future in the party.
“If it’s concluded that he started, he intentionally started, a fight - if, I stress, if - then that would be a black mark against his ability to stand.
“I think as a conclusion of that investigation the party will consider whether disciplinary measures are appropriate and that might have implications for Steven Woolfe’s candidacy,” the East Midlands MEP told BBC Radio Four’s Today programme.
Lisa Duffy, who was runner-up in last month’s leadership election, said party members were “embarrassed” by what had taken place.
“Do we want a leader who will get himself involved in an altercation, or do we want a leader who is going to be rational and reflect and deal with things in an appropriate manner?” she told the BBC.
“Violence or any kind of offering to go outside is not the way to deal with problems.”
Ukip MEP Jonathan Arnott said it was “obvious to anybody” that Mr Woolfe could no longer be a candidate.
“This really portrays Ukip in an appalling light,” he told BBC2’s Daily Politics programme.
“The people who have worked hard for this party, year in, year out - they expect better of their MEPs than what has been seen over the last 24 hours.”
European Parliament president Martin Schultz announced that he was launching an investigation into the conduct of the two MEPs, which could see them suspended from voting and their expenses cut.