Joe Biden has torn into Donald Trump for failing to distance himself from white power groups when asked at their debate last night.

In a tweet combining clips from the debate with footage from far-right events, Mr Biden was blunt. “There’s no other way to put it,” he wrote, “the President of the United States refused to disavow white supremacists on the debate stage last night.”

Mr Biden’s broadside comes as Mr Trump faces stinging criticism not only for declining to condemn white supremacy in general, but for telling the extremist right-wing Proud Boys to “stand back and stand by” – a message that the group has taken as a signal to prepare for post-election violence.

At the debate, moderator Chris Wallace pointed out to the president that for all his insistence on blaming the left for disorder in American cities without specifically condemning groups on the other side, many of whom have openly celebrated their own violent actions.

“You have repeatedly criticised the vice president for not specifically calling out Antifa and other left wing extremist groups,” said Mr Wallace. “But are you willing tonight to condemn white supremacists and militia group and to say that they need to stand down and not add to the violence in a number of these cities as we saw in Kenosha and as we’ve seen in Portland?”

“Sure, I’m willing to do that,” said the president – before once again blaming the left, not the right.

When pressed on the point, he refused to denounce far right groups in general, instead asking Mr Wallace for a name. The moderator and Mr Biden asked him about far-right militia and the Proud Boys; Mr Trump replied “Proud Boys? Stand back and stand by. But I’ll tell you what somebody’s got to do something about Antifa and the left because this is not a right wing problem.”

Mr Trump has for weeks now refused to guarantee a peaceful transfer of power after the election, repeatedly saying he will “wait and see” what the result is.

There’s no other way to put it: the President of the United States refused to disavow white supremacists on the debate stage last night.

— Joe Biden (@JoeBiden) September 30, 2020
Combined with his increasingly vehement insistence that the election is going to be stolen from him thanks to mail-in ballot fraud – of which there is no evidence – this has raised serious concerns that he and some of his supporters will endorse or even inflame violence among armed self-proclaimed militias.

As Mr Wallace pointed out to him, the Proud Boys and other groups have appeared at Black Lives Matter protests and other events throughout the summer. At one protest in Kenosha, 17-year-old Kyle Rittenhouse allegedly shot dead two people after answering a call for “patriots” to bring guns to the city and help law enforcement impose order.