US senators voted on Tuesday to move forward with Donald Trump's impeachment trial on a charge of inciting the deadly assault on the Capitol, rejecting a claim the proceeding was unconstitutional after viewing graphic video of the January attack.

The Senate voted 56-44 to proceed with its trial of the former president, a historic first, rejecting largely along party lines his defence lawyers' argument that a president cannot face trial after leaving the White House. Democrats hope to disqualify Trump from ever again holding public office.