Donald Trump has said there will be an "orderly transition" after the US Congress certified Joe Biden's win in the presidential election.

It comes just hours after deadly protests erupted in Washington DC - and after Congress formally validated Mr Biden's November victory, certifying his 306 Electoral College votes.

"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," the unswerving outgoing president 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!"

The statement was posted on Twitter by the president's deputy chief of staff Dan Scavino after the president was locked out of his social media accounts.

Twitter and Facebook also removed several posts by the president which made false claims about the election result and praised his supporters for the march in Washington DC to protest against his defeat.

It ended with dramatic scenes which saw the storming of the Capitol building by protesters to disrupt Congress's formal confirmation of Mr Biden's November win - and the deaths of four people.

Trump supporter and US Air Force veteran Ashli Babbitt died after being shot by a plain-clothed police officer as protesters attempted to enter the House Chamber where politicians were working to confirm the Electoral College votes in favour of Mr Biden.

Another three people died during the violence from "medical emergencies" and a curfew ordered across the city.

The FBI disarmed two suspected explosive devices in the capital as rioters flooded the streets and breached barricades, including one which resembled a pipe bomb.

The rioting was preceded by a rally in which Mr Trump told thousands of supporters, including members of far-right groups: "All of us here today do not want to see our election victory stolen by emboldened radical Democrats.

"We will never give up. We will never concede. It will never happen. You don't concede when there's theft involved. Our country has had enough. We will not take it anymore."

He said the outcome of the election was an "egregious assault on our democracy" and they should "walk down to the Capitol".

What started as a peaceful protest to overturn the election and prevent Mr Biden taking office from 20 January, turned violent, as the president's supporters attacked the Capitol building and clashed with police.

President-elect Biden condemned the violence and called on Mr Trump go on national television to "demand an end to this siege".

"This is not dissent. It's disorder. It's chaos. It borders on sedition and it must end now," Mr Biden said.

"I call on this mob to pull back and allow the work of democracy to go forward."