Video has emerged online of a Donald Trump supporter being punched in the head outside the 'Deploraball', an event to celebrate Trump’s inauguration in Washington.

James Allsup was wearing a Trump T-shirt and 'Make America Great Again' hat while debating an anti-Trump demonstrator outside the event on Thursday. An individual wearing a ski-mask and holding a banner reading 'antifascist' is seen in the video grabbing his hat and, in the altercation that follows, Allsup is punched by another individual, also wearing a ski mask.

Speaking to Fox News, Allsup, with blood gushing from his head, said he blacked out for a minute following the punch.

“I’m all for disagreeing, I debate people all the time and I want to engage in these discussions, but they’re throwing bottles,” he said. “I would be livid if people who supported Trump were doing this to Hillary [Clinton] supporters.”

The altercation happened outside the 'Deploraball', described by one Trump supporter as a “coming out party for a new type of Republican.” Some 1,000 Trump supporters attended the event at the city’s National Press Building, named after Hillary Clinton’s infamous “basket of deplorables” comment.

READ MORE: Massive anti-Trump protest at #DeploraBall in DC ahead of inauguration