The US Senate has acquitted former president Donald Trump in an impeachment trial for allegedly inciting an insurrection at the Capitol on January 6.

The trial which began on Tuesday was broadcast across the country.

Democrats from the House of Representatives, who served as prosecutors, presented the case. They showed new videos which were taken on the day the Capitol was stormed.

They accused Trump of repeatedly fanning supporters' frustration which led to the violent attack that resulted in deaths and injuries.

After closing arguments, the trial concluded with a vote by senators on Saturday afternoon.

Fifty-seven senators including 7 Republicans voted for impeachment, but it was short of the two-thirds majority required for conviction.

Many Republicans maintained the trial of a president who is no longer in office is unconstitutional.

Trump is the first US president to be impeached twice. He was acquitted the first time as well.