Former US President Donald Trump was acquitted Saturday on charges of inciting an insurrection at the US Capitol, after a majority of Senate Republicans closed ranks and refused to punish the former president in his historic second impeachment trial.

The five-day trial saw Democratic prosecutors argue -- bolstered by dramatic video of the January 6 riot -- that Trump betrayed his oath by whipping up his supporters into storming Congress in a last-ditch attempt to cling to power.

It concluded as expected with a majority of Republicans declaring him not guilty, in a sign of the powerful grip the 74-year-old Trump continues to exert on his party.

But while the 57-43 majority that voted to convict fell short of the two-thirds needed in the Senate, seven Republicans joined with Democrats to seek Trump's conviction, making it the most bipartisan impeachment trial in US history.