U.S. President-elect Joe Biden said Tuesday that President Donald Trump's refusal to concede defeat in last week's election is an "embarrassment," while playing down concerns that the incumbent's behavior may hamper work toward a smooth transition in January.

"I just think it's an embarrassment, quite frankly. The only thing that -- how can I say this tactfully -- I think it will not help the president's legacy," the 77-year-old Democrat, who was projected to be the election winner by U.S. media on Saturday, told reporters.

President-elect Joe Biden addresses the nation at the Chase Center Nov. 7, 2020 in Wilmington, Delaware. (Getty/Kyodo)  

Trump, the 74-year-old Republican president, has claimed that the election was rigged through "illegal" ballots, alluding to mail-in ballots that he has baselessly criticized as vulnerable to voter fraud. He has also insisted that Republican poll watchers were improperly denied access to observe the ballot-counting process in some locations.

The Trump campaign has filed lawsuits in several battleground states, although some of them have been quickly dismissed.

Concerns have grown that the dispute could complicate the process of transferring power, with Trump reportedly refusing to sign off on a key document that would allow Biden's team to gain access to government funds, officials and office space in agencies.

But Biden said Tuesday that the transition is "well underway," and that Trump's failure to concede "does not change the dynamic" of the process.

"We're going to be moving along in a consistent manner, putting together our administration, the White House, and reviewing who we're going to pick for the Cabinet positions, and nothing's going to stop that," the former vice president said.

Biden has already taken part in a flurry of phone calls with world leaders. He held talks with the Canadian prime minister on Monday and leaders of Britain, France, Germany and Ireland on Tuesday, according to his team.

Biden said he has assured world leaders that "America is back" and "it's not America alone" anymore, apparently drawing a contrast with Trump's "America First" foreign and trade policy that has often been criticized for undermining alliances, multilateralism and international organizations.

During the talks, the president-elect showed interest in reinvigorating bilateral and trans-Atlantic ties, including through the North Atlantic Treaty Organization and the European Union, and discussed the coronavirus pandemic, global economic recovery and climate change, according to a press release from his team.

Biden has campaigned on a platform to restore U.S. leadership on the global stage such as by rejoining the Paris climate accord and the World Health Organization from which Trump withdrew the United States.

Despite the diplomatic activities involving Biden, Secretary of State Mike Pompeo shrugged off the election results showing Trump's defeat.

"There will be a smooth transition to a second Trump administration," Pompeo told a press conference on Tuesday when asked about how the State Department is preparing to engage with the Biden transition team.

U.S. media on Saturday projected that Biden had won a majority of the 538 state-by-state Electoral College votes, leading him to declare victory later in the day.

Under the Electoral College system, the election results will be formalized through a vote by electors in their respective states on Dec. 14 and through the count of the votes by Congress on Jan. 6.

The president-elect and vice president-elect will be sworn in at noon on Jan. 20, a date that is stipulated in the Constitution.