Donald Trump and Joe Biden traded bitter insults as their televised clash descended into what has been described by US pundits as 'the worst presidential debate ever' - and 'a sh*tshow'.

The first TV debate of the 2020 election has been branded a "national embarrassment" after Trump derailed it with frequent interruptions and barracking.

The US president refused to condemn white supremacist groups and again hinted that he wouldn't accept the result of November's election

Trump was branded a 'clown' and told to 'shut up' by Joe Biden as the debate descended into farce, the Mirror reports.

CNN presenter Jake tapper later described the debate as 'a hot mess, inside a dumpster fire, inside a train wreck' saying: "That was the worst debate I have ever seen. It wasn't even a debate. It was a disgrace. And it's primarily because of Donald Trump."

His colleague Dana Bash said: "That was a sh*tshow."

CLEVELAND, OHIO - SEPTEMBER 29: U.S. President Donald Trump participates in the first presidential debate against Democratic presidential nominee Joe Biden at the Health Education Campus of Case Western Reserve University on September 29, 2020 in Cleveland, Ohio. This is the first of three planned debates between the two candidates in the lead up to the election on November 3. (Photo by Win McNamee/Getty Images)

The President left both Biden and moderator Chris Wallace frustrated after he repeatedly interrupted them during the first segment of the 90 minute showdown.

During the "car crash" debate, Trump also refused to condemn white supremacists and wouldn't promise not to declare victory before the ballots are counted.

Watch: Biden tells Trump 'you're the worst president America has ever had'

As the debate kicked off, Trump constantly interrupted Biden and broke the rules by continuing to speak past his two-minute limit.

"Can you see what this clown is doing?", Biden fumed.

"Would you shut up, man? That was a real productive segment. Keep on yapping."

The pair then clashed over Trump's plan to rapidly install his nominee to the US Supreme Court to replace the late Justice Ruth Bader Ginsburg.

Biden addressed fears from many voters that the Republicans plan to install conservative judge Amy Coney Barrett in order to tear up the Affordable Care Act, which is relied upon by millions for healthcare.

Mr Wallace was forced to shout over the bickering candidates after the second segment as the debate descended into personal attacks and constant interruptions.

CLEVELAND, OHIO - SEPTEMBER 29: Democratic presidential nominee Joe Biden participates in the first presidential debate against U.S. President Donald Trump at the Health Education Campus of Case Western Reserve University on September 29, 2020 in Cleveland, Ohio. This is the first of three planned debates between the two candidates in the lead up to the election on November 3. (Photo by Win McNamee/Getty Images)

"Gentleman!" he shouted. "I hate to raise my voice but why shouldn't I be different to the two of you?"

They continued to move through an array of urgent political topics, including the coronavirus pandemic before landing on the ongoing protests for racial justice.

Trump was left stuttering after being urged to condemn the far-right white supremacists and citizen military groups responsible for much of the violence at demonstrations, while also often voicing support for him.

When pressed further by Mr Wallace, Trump said: "What do you want to call them? Give me a name. Give me a name?"

Finally, he said: "Proud Boys - Stand back, stand by, but I'll tell you what, somebody's got to do something about Antifa and the left because this is not right-wing problem... This is a left wing problem."

CLEVELAND, OHIO - SEPTEMBER 29: U.S. President Donald Trump and first lady Melania Trump on stage after the first presidential debate between Trump and Democratic presidential nominee Joe Biden at the Health Education Campus of Case Western Reserve University on September 29, 2020 in Cleveland, Ohio. This is the first of three planned debates between the two candidates in the lead up to the election on November 3. (Photo by Win McNamee/Getty Images)

As things began to heat up, the President then refused to promise he won't claim victory in the election before all votes are counted and independently verified.

And he urged his supporters to go to polling places on election day and watch for evidence of "fraud" - adding "This is not going to end well".

Even before the debate started, it was clear this was going to be a bare-knuckle fight.

Team Biden declined - also denying, as Trump’s team claimed, that they had asked for “multiple breaks” during the event.

Kate Bedingfield, a Biden deputy campaign manager said Team Trump “seems concerned that he will not do well tonight, and they’re already laying the groundwork for how they’re going to lie about why.”

She added: “It is completely absurd. Of course he is not wearing an earpiece, and we never asked for breaks.”

There was no opening handshake on Tuesday night because of Covid-19, but the body language between Trump and Biden still took centre stage.

Trump scowled at his rival for much of the debate, or wagged his finger or waved his hand to dismiss his Democratic opponent.

Biden, meanwhile, regularly gazed into the camera when Trump interrupted him to make a direct appeal to the American people.

WEST HOLLYWOOD, CALIFORNIA - SEPTEMBER 29: A server wears a face shield and face covering as people sit and watch a broadcast of the first debate between President Donald Trump and Democratic presidential nominee Joe Biden at The Abbey with socially distanced outdoor seating on September 29, 2020 in West Hollywood, California. The debate being held in Cleveland, Ohio is the first of three scheduled debates between Trump and Biden. (Photo by Mario Tama/Getty Images)

Trump "doesn't want to talk about what you need - you, the American people. It's about you," Biden said at one point.

Trump didn't mince words when Mr Wallace asked him what he paid in federal income taxes in 2016 and 2017, after the New York Times reported that his tax returns showed only a $750 payment in each year.

Offering no evidence, Trump said he had paid, "millions of dollars. And you'll get to see it," despite his refusal to release any returns since he became a candidate in 2015, breaking with decades of tradition.

"Show us your tax returns," Biden interjected.

When Mr Wallace turned to Biden, the Democrat quickly pivoted to his economic plan, saying he would repeal Trump's tax cuts that largely benefited corporations and the wealthy, and the discussion turned to the trillions of dollars those proposals represent.

CLEVELAND, OHIO - SEPTEMBER 29: Democratic presidential nominee Joe Biden participates in the first presidential debate against U.S. President Donald Trump at the Health Education Campus of Case Western Reserve University on September 29, 2020 in Cleveland, Ohio. This is the first of three planned debates between the two candidates in the lead up to the election on November 3. (Photo by Win McNamee/Getty Images)

Biden questioned Trump's leadership on the coronavirus pandemic, saying Trump had panicked and failed to protect Americans because he was more concerned about the economy.

"He panicked or he looked at the stock market," Biden said of Trump, who has pushed for states to reopen their economies and played down the threat of the pandemic.

"A lot of people died and a lot more are going to die unless he gets a lot smarter, a lot quicker," Biden said.

Trump objected to Biden using the word "smart."

CLEVELAND, OHIO - SEPTEMBER 29: U.S. President Donald Trump (R) and Democratic presidential nominee Joe Biden participate in the first presidential debate at the Health Education Campus of Case Western Reserve University on September 29, 2020 in Cleveland, Ohio. This is the first of three planned debates between the two candidates in the lead up to the election on November 3. (Photo by Olivier Douliery-Pool/Getty Images)

"You graduated either the lowest or almost the lowest in your class. Don't ever use the word smart with me. Don't ever use that word,'' Trump said.

He defended his approach on the pandemic, which has killed more than 200,000 people in the United States and put millions of Americans out of work.

"We've done a great job," Trump said. "But I tell you, Joe, you could never have done the job we've done. You don't have it in your blood."

Early voting is underway in many states, with the election just 35 days away.