US President Joe Biden has slammed Donald Trump for kowtowing to Russia, failing to care about COVID-19 and papering over the January 6 Capitol assault in a State of the Union speech aimed at showing his capacity to take on a second term in office.

Biden, speaking before a joint session of the House of Representatives and the Senate on Thursday (US time), opened his remarks with a direct criticism of Trump for comments inviting Russian President Vladimir Putin to invade other NATO nations if they did not spend more on defence.

“Now my predecessor, a former Republican president, tells Putin, quote, ‘Do whatever you want’,” Biden said.

“I think it’s outrageous, it’s dangerous and it’s unacceptable.”

Biden, who has pushed Congress to provide additional funding to Ukraine for its war with Russia, also had a message for Putin: “We will not walk away,” he said.

Biden drew a contrast with Trump, his Republican challenger in the November 5 presidential election, over democracy, abortion rights and the economy during a speech that Democrats see as a high-profile chance for him to press his case for a second term in front of a TV audience of millions of Americans.

Biden came out swinging at the top of his speech, accusing Trump and Republicans of trying to rewrite history about the Capitol riot by the former president’s supporters seeking to overturn Biden’s 2020 victory.

“My predecessor and some of you here seek to bury the truth about January 6. I will not do that,” Biden said, a signal that he will emphasise the issue during his re-election campaign.

“You can’t love your country only when you win.”

He also knocked Republicans for seeking to roll back healthcare provisions under the Affordable Care Act, also known as Obamacare, and driving up deficits and jibed them for taking money from legislation they had opposed.

Suffering from low approval ratings, Biden faces discontent among progressives in his party about his support for Israel in its war against Hamas and from Republicans over his stance on immigration, but the mood among Democrats in the chamber was rapturous. They greeted Biden with cheers and applause, prompting him to quip that he should leave before he even began.

Trump, meanwhile, sent a steady stream of messages blasting Biden on his Truth Social platform.

“He looks so angry when he’s talking, which is a trait of people who know they are ‘losing it,'” Trump wrote.

“The anger and shouting is not helpful to bringing our Country back together!”

Tweet from @LauraLoomer

Opinion polls show Biden, 81, and Trump, 77, closely matched in the race. Most American voters are unenthusiastic about the rematch after Biden defeated Trump four years ago.

Trump, facing multiple criminal charges as he fights for re-election, says he plans to punish political foes and deport millions of migrants if he wins a second White House term.

Biden took direct aim at concerns about his age in powerful closing remarks.

“I know I may not look like it, but I’ve been around a while,” he said.

“When you get to my age certain things become clearer than ever before. I know the American story.”

He also sought to burnish his reputation about the strength of the US economy and renew his quest to make wealthy Americans and corporations pay more in taxes.

Any such tax reform is unlikely to pass unless Democrats win strong majorities in both houses of Congress in the November vote, which is not forecast.

Biden also proposed new measures to lower housing costs, including a $US10,000 ($15,100) tax credit for first-time homebuyers – an acknowledgement of consumers’ distress at high mortgage interest rates.

The US economy is performing better than most high-income countries, with continued job growth and consumer spending.

However, Republican voters tell pollsters they are deeply dissatisfied with the economy, and Americans overall give Trump better marks in polls for economic issues.

Biden has also tried to cool anger among many Democrats over his support for Israel’s offensive in Gaza following the October 7 Hamas attacks. He’s announced that the US military will build a port on Gaza’s Mediterranean coast to receive humanitarian assistance by sea.

He again pushed for a $95 billion aid package for weapons to Ukraine and aid to Israel that has been blocked by Republican House Speaker Mike Johnson.

Guests at the address included Swedish Prime Minister Ulf Kristersson, who was in Washington as Sweden formally joins NATO, people affected by in vitro fertilisation or abortion restrictions, a veteran of the 1965 Bloody Sunday attack on Black marchers in Selma, Alabama, United Auto Workers President Shawn Fain and others.

US Senator Katie Britt of Alabama, will deliver Republicans’ formal response to Biden’s speech.

-with AAP