US President Obama meet to his winner Donald Trump for talks aimed at ensuring a smooth transition of power.
Trump will become the 45th US president after securing a surprise victory over Hillary Clinton.
But the president has now urged all Americans to accept the result of Tuesday's election.
"We are now all rooting for his success in uniting and leading the country," Barack Obama said of Mr Trump.
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Despite Mr Obama's calls for unity and Mrs Clinton telling supporters Mr Trump must be given a "chance to lead," his victory has sparked protests in several US states.
Hundreds of Anti-Trump demonstrators in New York staged a march on Trump Tower in Manhattan on Wednesday evening, waving placards declaring "Not my president" and other slogans.
In Oakland, California, and Portland, Oregon, protesters have reportedly burned American flags.
The president-elect, who has never held elected office, has said his immediate priorities will be restoring the country's infrastructure and doubling its economic growth.
Republican National Committee Chairman Reince Priebus said: "Donald Trump is taking this very seriously," adding that the business mogul's deal-making ability would enable him to quickly "make things happen for the American people".