Starbucks has become embroiled in a debate around Donald Trump after two supporters claimed they were mistreated by staff due to their political allegiances.

The coffee chain started to trend on Twitter with the hashtag #TrumpCup after a Starbucks employee allegedly called police on a customer for requesting the name "Trump" on his coffee cup.

In the second case, a video of Trump supporter David Sanguesa berating a Starbucks barista for allegedly refusing to serve him went viral.

A witness, as reported by the Washington Post, said Mr Sanguesa got angry because his coffee order was taking too long, and Mr Sanguesa said he has been "harassed by people all over the country".

Customers are now calling themselves "Trump" at the coffee chain in protest against what they view as “anti-white discrimination”.

Mr Sanguesa told ABC News that he and a colleague met at a Starbucks near Miami on Wednesday and claimed the barista would not serve him. He suggested that the service was evidence of "anti-white discrimination" because he had a Trump sign on his car.

The Starbucks employee told the Miami Herald she had not refused service to Mr Sanguesa.

A witness, Jorge de Cárdenas, told the same newspaper that another customer told Mr Sanguesa he was an "**hole" and he replied "F*** you, b***h".

Mr Cárdenas filmed him asking for a refund and lashing out.

"We want nothing to do with you," he told the barista, a woman of colour. "You’re trash."

"So what?" she replied.

"Because I voted for Trump! Trump! You lost! Now give me my money back. What is your name? I want your name. I want your card. You’re garbage. You’re complete trash."

Other customers intervened and Mr Sanguesa appealed to another employee as to whether he had heard the exchange. He then threatened to punch that employee.

The Miami Herald reported that Mr Sanguesa was charged twice in 2008 of drinking while under the influence. Six years later, he was charged with domestic violence, but the charge was later dropped.

The newspaper said for years it had received emails from him which were anti-women and anti-gay in content.

"I was racially discriminated against," Mr Sanguesa told the New Times. "This is bulls**t .I’m a business owner. I didn’t deserve this. That woman refused to serve us coffee."

He said that what he had said to the barista was wrong and he had apologised, but that the harassment from other people had gone "out of control".