Hillary Clinton has slammed Donald Trump on Twitter branding him an "ignorant racist'.

Trump's former political rival was reacting to remarks reportedly made by the President during a briefing session in the Oval Office when he is alleged to have launched into a rant against immigrants.

Trump was quoted in the Washington Post as having said: 'Why are we having all these people from s***hole countries come here?' during a discussion regarding plans to overhaul the immigration system in which he is said to have specifically made derogatory remarks in reference to Haiti, El Salvador and African countries.

Clinton, who was defeated by Trump in the presidential election, took the opportunity to hit back on social media tweeting: "The anniversary of the devastating earthquake 8 years ago is a day to remember the tragedy, honor the resilient people of Haiti, & affirm America's commitment to helping our neighbors," Clinton said.

"Instead, we're subjected to Trump's ignorant, racist views of anyone who doesn't look like him."

Her comment comes at the end of a long day for the President, who has been almost universally lambasted for his vulgar language and his distinctly unpresidential conduct.

Responding to the backlash on Friday, Trump admitted using strong language in the course of the briefing, but denied using expletives, claiming that was not the "language used" as he also denied saying "anything derogatory about Haitians."

"The language used by me at the DACA meeting was tough, but this was not the language used," he tweeted.

However, a senior Democrat who was sitting next to the President at the time, remembers the meeting very differently. Democratic Sen. Richard Durbin of Illinois on Friday said Trump had indeed made the comments about 's***hole countries.'

"I cannot believe that in the history of the Oval Office any president has spoken the words that I have personally heard the President speak yesterday," said Durbin, clearly appalled.

"You've seen the comments in the press," he explained. "I have not read one of them that's inaccurate. To no surprise, the President started tweeting this morning, denying that he used those words. It is not true. He said these hate-filled things and he said them repeatedly."

hillary clinton
Hillary Clinton lashes out at her former political foe on Twitter amid the latest controversy Saul Loeb/AFP/Getty Images)

The reports prompted the United Nations to publicly condemn the President issuing a stern reubke. "These are shocking and shameful comments from the President of the UNited states ... There is no other word for it but racist. You cannot dismiss entire countries and continents as "s***holes."

Vice President Joe Biden too felt compelled to challenge President Trump for his racist rhetoric saying 'We're better than this.'

"It's not how a president should speak. It's not how a president should behave. Most of all, it's not what a president should believe. We're better than this," Biden tweeted on Friday.

The latest controversy for Trump comes as he announced that he would not be making an official visit to the UK, declining an invitation to open the new US embassy in London, after describing the new move as"a bad deal."

A statement from the US Embassy defended its move to Nine Elms in Battersea, south London explaining that the new building "meets all security standards, yet used no tax payer dollars to fund the project."

"We are strongly committed in the Special Relationship between our two countries and we are confident the new Embassy will provide the necessary platform to continue our cooperation," the statement read.