Washington DC: Joe Biden said Donald Trump’s refusal to concede the election was “an embarrassment”, vowing to move forward with the presidential transition despite resistance from the White House and Republican leaders.

Biden, answering questions for the first time since he was declared the winner of the 2020 election, intensified his criticism of the president, who continued to baselessly allege voter fraud, and said Trump’s denial would “not help his legacy”.

"I just think it's an embarrassment, quite frankly," Biden, a Democrat, said in Wilmington, Delaware.

"The only thing that, how can I say this tactfully, I think it will not help the president's legacy."

"At the end of the day, you know, it's all going to come to fruition on January 20," he added, referring to inauguration day.

Also read: US President Donald Trump claims he’s immune to COVID-19

But the US president-elect - who has been making contact with foreign leaders - insisted nothing would stop the transfer of power.

UK Prime Minister Boris Johnson, Irish Taoiseach Micheál Martin, French President Emmanuel Macron and German Chancellor Angela Merkel were among those he spoke to on Tuesday.

Trump meanwhile tweeted he would ultimately win the race that all major TV networks have forecast he lost.

As happens every four years, US media projected the election victor.

Though the situation at the White House has caused deepening alarm over whether the US would witness a smooth transfer of power that has been a hallmark of American democracy for generations, Biden promised his team was “going to get right to work” confronting the compounding crises facing the nation.