Donald Trump was acquitted on Saturday of inciting the horrific attack on the US Capitol, concluding a historic impeachment trial that spared him the first-ever conviction of a current or former US president.

Barely a month since the deadly January 6 riot that stunned the world, the Senate convened for a rare weekend session to deliver its verdict, voting while armed National Guard troops continued to stand their posts outside the iconic building.

The quick trial, the nation's first of a former president, showed in raw detail how close the invaders had come to destroying the nation's deep tradition of a peaceful transfer of presidential power after Mr Trump had refused to concede the election.

Rallying outside the White House, he unleashed a mob of supporters to "fight like hell" for him at the Capitol just as Congress was certifying Democrat Joe Biden's victory.

As hundreds stormed the building, some in tactical gear engaging in bloody combat with police, lawmakers fled for their lives. Five people died.

The verdict, on a vote of 57-43, is all but certain to influence not only the former president's political future but that of the senators sworn to deliver impartial justice as jurors. Seven Republicans joined all Democrats to convict, but it was far from the two-third threshold required.

The outcome after the uprising leaves unresolved the nation's wrenching divisions over Mr Trump's brand of politics that led to the most violent domestic attack on one of America's three branches of government.

Mr Trump, unrepentant, welcomed his second impeachment acquittal and said his movement "has only just begun". He slammed the trial as "yet another phase of the greatest witch hunt in the history of our Country".

Though he was acquitted of the sole charge of incitement of insurrection, it was easily the largest number of senators to ever vote to find a president of their own party guilty of an impeachment count of high crimes and misdemeanours.

Voting to find Mr Trump guilty were GOP senators Richard Burr of North Carolina, Bill Cassidy of Louisiana, Susan Collins of Maine, Lisa Murkowski of Alaska, Mitt Romney of Utah, Ben Sasse of Nebraska and Patrick Toomey of Pennsylvania.

Even after voting to acquit, the Republican leader Mitch McConnell condemned the former president as "practically and morally responsible" for the insurrection. Mr McConnell contended Mr Trump could not be convicted because he was gone from the White House.

In a statement issued several hours after the verdict, Mr Biden highlighted the bipartisan nature of the vote to convict as well as Mr McConnell's strong criticism of Mr Trump.

In keeping with his stated desire to see the country overcome its divisions, Mr Biden said everyone, especially the nation's leaders, had a duty "to defend the truth and to defeat the lies".

"That is how we end this uncivil war and heal the very soul of our nation. That is the task ahead. And it's a task we must undertake together," said Mr Biden, who had hardly weighed in on the proceedings during the week.

The trial had been momentarily thrown into confusion when senators on Saturday suddenly wanted to consider potential witnesses, particularly concerning Mr Trump's actions as the mob rioted.

Prolonged proceedings could have been especially damaging for Mr Biden's new presidency, significantly delaying his emerging legislative agenda. Coming amid the searing Covid-19 crisis, the Biden White House is trying to rush pandemic relief through Congress.

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The nearly week-long trial delivered a grim and graphic narrative of the riot and its consequences in ways that senators, most of whom fled for their own safety that day, acknowledge they are still coming to grips with.

House prosecutors have argued that Mr Trump was the "inciter in chief", stoking a months-long campaign with an orchestrated pattern of violent rhetoric and false claims they called the "big lie" that unleashed the mob. Five people died, including a rioter who was shot and a police officer.

Mr Trump's lawyers countered that his words were not intended to incite the violence and that impeachment was nothing but a "witch hunt" designed to prevent him from serving in office again.

The senators, announcing their votes from their desks in the very chamber the mob had ransacked, were not only jurors but also witnesses.

READ MORE: Trump impeachment: Senators set to vote with acquittal expected

HeraldScotland:

Only by watching the graphic videos - rioters calling out menacingly for House Speaker Nancy Pelosi and Vice President Mike Pence, who was presiding over the January certification tally - did senators say they began to understand just how perilously close the country came to chaos.

Many senators kept their votes closely held until the final moments on Saturday, particularly the Republicans representing states where the former president remains popular. Most of them ultimately voted to acquit, doubting whether Mr Trump was fully responsible or if impeachment was the appropriate response.

"Just look at what Republicans have been forced to defend," said Senate majority leader Chuck Schumer. "Look at what Republicans have chosen to forgive."

The second-ranking Republican, John Thune of South Dakota, acknowledged, "It's an uncomfortable vote," adding: "I don't think there was a good outcome there for anybody."