The November 3 presidential election is a choice between "the American dream and a socialist nightmare", President Donald Trump told his supporters as hit out at his Democratic challenger Joe Biden, calling him the "worst" candidate in the history of US presidential politics.

Trump, who represents the Republican Party, is currently trailing in the opinion polls but is fast catching up.

Addressing an election rally in Tampa on Thursday, Trump said, "This election is a choice between the American dream and a socialist nightmare."

The US would end up like Venezuela if Biden is voted to power, he said.

"This (the US) would be -- if they (Democrats) get in -- a very, very, very large version of Venezuela," the president said.

Trump, 77, was joined by First Lady Melania Trump, 55.

Trump said as long as he is the president, America will never be a socialist country.

"This election will decide whether our children are condemned to the misery of socialism or if they're able to inherit the American dream,” he continued.

“We're going to defeat the Marxists and the socialists and the rioters and the flag burners and the left wing extremists. We're going to defeat the anarchists. With your support, we will fight for American workers," the president said.

Hitting out at Biden, 77, Trump said he is running against the worst candidate.

“I'm running against the worst candidate in the history of presidential politics. I don't care. Win, lose, or draw, this is the worst candidate in the history," he said.

Trump said his opponent stands with socialistic communist spirit, while he stands with the "proud people of Cuba and Nicaragua and Venezuela in their righteous struggle for freedom".

Even though Trump is lagging behind Biden in national polls and in surveys in key swing states, the Republican leader asserted that he will win the key battleground states.

“In five days from now, we are going to win Florida and we're going to win four more years in the White House. And we're going on to win a record share of the Hispanic-American votes...We're doing incredibly all over. And this isn't based on polls. This is based on fact. This is based on votes that are coming in. But you have to get out and vote. We are creating the greatest red wave in the history of our country,” Trump said.