Bush, Obama to eulogize McCain at US senator's final farewell

Late US senator John McCain will receive his final public sendoff Saturday in a nationally televised ceremony featuring eulogies from two ex-presidents, but with current commander in chief Donald Trump conspicuously absent from the proceedings.

Republican George W Bush and Democrat Barack Obama will deliver remarks honouring their friend and former White House challenger, at a memorial service in Washington's National Cathedral that McCain planned himself in recent months as he battled brain cancer.

That the men who vanquished McCain in their presidential battles were asked to speak is testament to the former war prisoner's commitment to looking beyond party and signalling that Americans, regardless of political affiliation, are rowing together in the same boat.

Amid today's inflammatory political environment the message could serve as a soothing balm for a nation bruised by two years of divisive discourse.

And the absence of Trump, whose bitter feud with McCain has wrangled US politics during that time, will serve as a final rebuke of the president, highlighting the clash between a Republican elder statesman and the current president from his own party.

McCain's last public event, before he is laid to rest Sunday in a private ceremony at the US Naval Academy in Annapolis, Maryland, comes a day after he was accorded the rare recognition of lying in state in the US Capitol.

While members of Congress honoured one of their own in a touching ceremony that featured an address by Vice President Mike Pence, Trump was again not there.

Instead he holed up in the White House and remained uncharacteristically silent on Twitter during the ceremony, before flying to a political event in North Carolina later in the day.

McCain's widow Cindy, his seven children and his 106-year-old mother Roberta McCain joined scores of members of Congress, state governors, diplomats and other dignitaries at the somber Rotunda ceremony.

Pence, in his tribute, told McCain's family that "it is deeply humbling to stand before you today at the United States Capitol to commemorate the life and service of an American patriot."