Donald Trump was “completely wrong” to incite supporters to storm the Capitol and to continue questioning the legitimacy of the US election, Boris Johnson said.
The Prime Minister – who has enjoyed a warm relationship with the US President – said he “unreservedly” condemned Mr Trump’s actions following the extraordinary events in Washington.
Joe Biden was confirmed as the president-elect despite the violent scenes as a pro-Trump mob stormed the Capitol in an attempt to disrupt the proceedings.
Mr Johnson, who was born in the US, told a Downing Street press conference: “All my life, America has stood for some very important things – an idea of freedom and an idea of democracy.”
In response to a question about Mr Trump’s responsibility for the scenes in Washington, Mr Johnson said: “Insofar as he encouraged people to storm the Capitol and insofar as the president consistently has cast doubt on the outcome of a free and fair election I believe that that was completely wrong.
“I think what President Trump has been saying about that has been completely wrong.
“I unreservedly condemn encouraging people to behave in the disgraceful way that they did in the Capitol.
“And all I can say is I’m very pleased that the president-elect has now been duly confirmed in office and that democracy has prevailed.”
In Washington, House Speaker Nancy Pelosi said Mr Trump should immediately be removed from office or Congress could move to impeach him.
Ms Pelosi joined calls for the cabinet to invoke the 25th Amendment to force Mr Trump from office.
“The president of the United States incited an armed insurrection against America,” she said.
Earlier, Facebook announced it was blocking Mr Trump “indefinitely and for at least the next two weeks” following the rioting.
The social network’s boss Mark Zuckerberg said it was clear that Mr Trump intended to use his remaining time in office “to undermine the peaceful and lawful transition of power to his elected successor, Joe Biden”.
“We believe the risks of allowing the president to continue to use our service during this period are simply too great,” Mr Zuckerberg said.
“Therefore, we are extending the block we have placed on his Facebook and Instagram accounts indefinitely and for at least the next two weeks until the peaceful transition of power is complete.”
Mr Trump’s incendiary comments have been blamed for directly provoking the violence which left four dead, including protester Ashli Babbitt who was shot by police.
Home Secretary Priti Patel said his statement following events at the Capitol on Wednesday, in which he said “we love you” to the rioters and repeated his baseless claims of electoral fraud, did “very little to de-escalate the situation”.
“His comments directly led to the violence and so far he has failed to condemn that violence, and that is completely wrong,” the Home Secretary said.
Mr Trump’s personal Twitter account was also temporarily suspended, forcing him to release a statement via his social media director Dan Scavino, saying there would be an “orderly transition” to the Biden administration.
“Even though I totally disagree with the outcome of the election, and the facts bear me out, nevertheless there will be an orderly transition on January 20th,” he said.
“I have always said we would continue our fight to ensure that only legal votes were counted.
“While this represents the end of the greatest first term in presidential history, it’s only the beginning of our fight to Make America Great Again.”
Tech giants have long struggled with balancing free speech on their platforms and a belief that the views of world leaders should be visible for scrutiny.
The main two, Facebook and Twitter, have slowly taken a tougher stance, using fact check labels last year to warn users of unverified information shared by Mr Trump.
Pressure is now on Twitter to follow Facebook’s lead, having only decided to lock Mr Trump’s personal account for 12 hours and threatened him with “permanent suspension” if he continues to break the rules.
A Twitter spokesperson said: “As we shared yesterday, we’re continuing to evaluate the situation in real-time, including examining activity on the ground and statements made off Twitter.
“We will keep the public informed, including if further escalation in our enforcement approach is necessary.”