Neo-Nazi and white supremacist groups descended on Shelbyville, Tennessee, US, on Saturday for an organised White Lives Matter rally.
The rally attracted hundreds of anti-racist protesters who easily outnumbered the white nationalists.
The couple, a 30-year-old white woman and a 37-year-old black man, were eating inside the Corner Pub in Brentwood – a town around 50 miles north of Shelbyville.
Nashville police said a group of around 20 to 30 white men and women came into the pub and sat behind them.
The woman later told police that one of the group members asked her to ‘guess’ and she responded ‘white lives matter’.
Another is believed to have said ‘that’s right’ before telling her to join their table and leave her boyfriend.
‘The argument inside apparently escalated even after the female victim had gone outside to de-escalate the situation,’ police said.
While she was arguing with another woman outside, a man punched her in the face ‘causing a cut above her eye’, the police statement added.
Annelise Werme was in the same pub when the violence broke out.
She posted a shocking video online of the couple attempting to push others away outside the restaurant.
Blood can be seen streaming down the woman’s face.