Joe Biden has said President Donald Trump's refusal to concede defeat in last week's White House election is "an embarrassment".
But the US president-elect - who has been making contact with foreign leaders - insisted nothing would stop the transfer of power.
Mr Trump meanwhile tweeted he would ultimately win the race that he has been projected to lose.
As happens every four years US media projected the winner of the election. None of the state-by-state results have yet been certified, several vote counts are continuing, and the outcome will only be set in stone once the US Electoral College meets on 14 December.
The president-elect was asked by a reporter on Tuesday what he thought of President Trump's refusal to acknowledge defeat.
"I just think it's an embarrassment, quite frankly," Mr 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.