U.S. President Donald Trump on Sunday publicly acknowledged for the first time that Democratic challenger Joe Biden won the Nov. 3 presidential election, but later emphasized that he has no intention of conceding what he views as a "rigged" race.

"He won because the Election was Rigged," the 74-year-old Republican president tweeted. In another tweet posted more than an hour later, Trump said, "He only won in the eyes of the FAKE NEWS MEDIA. I concede NOTHING!"

U.S. President Donald Trump speaks at the White House on Nov. 5, 2020, in Washington. (Getty/Kyodo)

Concerns are growing that Trump's continued refusal to admit defeat a week after Biden was declared the winner by major U.S. media outlets could hamper the smooth transition of power slated for Jan. 20.

Ron Klain, who has been named as White House chief of staff by the president-elect, told NBC News on Sunday that he wants to see federal government "ascertainment" of Biden as the next president this week to allow his team access to government funds, officials and other resources to prepare for the transition.

"What we really want to see this week...is the General Services Administration issue that ascertainment so we can start to do the kinds of things," such as getting intelligence briefings for the president-elect, Klain said.

Trump 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 and which have favored his Democratic rival.

He has also insisted that Republican poll watchers were improperly denied access to observe the ballot-counting process in some locations, and most recently spread an unsubstantiated claim that a voting machine system at some polling stations deleted votes cast for the president.

The Trump campaign has filed lawsuits in several battleground states, but election experts are skeptical that the move will lead to the results being overturned.

President-elect Joe Biden leaves after attending mass at St. Joseph on the Brandywine Roman Catholic Church on November 15, 2020 in Wilmington, Delaware. (Getty/Kyodo)


Even a government agency overseeing the security of the electoral process posted on its website last Thursday a statement asserting that the Nov. 3 election was "the most secure in American history" and that "there is no evidence that any voting system deleted or lost votes, changed votes, or was in any way compromised."

A losing presidential candidate typically concedes shortly after the outcome is known.

But Trump suggested that he will continue to dispute the results, tweeting Sunday, "We have a long way to go. This was a RIGGED ELECTION!"

In the race for the White House, a winning candidate needs to secure at least 270 of the 538 Electoral College votes allocated to the 50 states and the District of Columbia. The candidate who wins the popular vote in a state captures that state's electoral votes, usually in a winner-take-all manner.

According to U.S. media projections, Biden, the 77-year-old former vice president under Trump's predecessor Barack Obama, has secured a total of 306 electoral votes against 232 for Trump.