But protesters vow to shut down or disrupt ceremony in Washington

Billionaire Republican Donald Trump on Thursday pledged to bring unity to the United States as he swept into Washington on the eve of the most consequential moment of his life - his inauguration as 45th president of the country.

On Friday, Trump was scheduled to cap an extraordinary and improbable run for the White House when he takes the reins from President Barack Obama at midday, launching the nation into uncharted waters.