(ATTN: CHANGES lead; UPDATES with additional information in paras 4, 28-36)
By Byun Duk-kun
WASHINGTON, Nov. 8 (Yonhap) -- Joe Biden was declared the winner of the U.S. presidential election on Saturday after a stunning upset victory in Pennsylvania amid expectations his election would strengthen the alliance with South Korea and bring changes to how the United States deals with North Korea.
Biden bagged the 20 electoral college votes of Pennsylvania to surpass the 270 electoral votes needed to win the White House after also winning in two more key battleground states -- Michigan and Wisconsin -- that were all won by President Donald Trump in the 2016 election.
Major media outlets here, including CNN, AP and NBC, called the state for Biden after his lead over Trump in Pennsylvania exceeded 34,000.
Vote counting was still under way in Florida, North Carolina and Arizona, but regardless of election results in those states, Biden is projected to have secured the minimum 270 electoral votes to win the presidency.
Biden and his running-mate Kamala Harris will be inaugurated on Jan. 20 should election projections hold and become certified next month.
Biden expressed gratitude and vowed to become "a president for all Americans."
"America, I'm honored that you have chosen me to lead our great country. The work ahead of us will be hard, but I promise you this: I will be a President for all Americans -- whether you voted for me or not," he tweeted.
He also called for unity in a separate statement.
"With the campaign over, it's time to put the anger and the harsh rhetoric behind us and come together as a nation," Biden said. "It's time for America to unite. And to heal. We are the United States of America. And there's nothing we can't do, if we do it together."
Biden was scheduled to address the nation in a press conference later in the day, according to his campaign.
Hundreds and thousands of Biden supporters were seen pouring out to the streets to celebrate throughout the nation.
Trump refused to concede.
"I WON THIS ELECTION, BY A LOT!" he tweeted, shortly after most major news outlets here called Pennsylvania in favor of Biden.
Trump has already threatened to challenge vote counts in some states where he lost, including Wisconsin.
"There have been reports of irregularities in several Wisconsin counties which raise serious doubts about the validity of the results," said Bill Stepien, Trump's campaign manager. The Trump campaign later said it will demand a recount of votes in Wisconsin.
Trump has also accused the Democrats of "ballot dumping," claiming that illicit and unaccounted-for votes that have been "dumped" in many battleground states were the only thing that made his earlier leads disappear.
"How come every time they count mail-in ballot dumps they are so devastating in their percentage and power of destruction?" Trump tweeted early Wednesday when his earlier leads in Wisconsin and Michigan were overtaken by Biden.
"Last night I was leading, often solidly, in many key states, in almost all instances Democrat run and controlled. Then, one by one, they started to magically disappear as surprise ballot dumps were counted. Very strange, and the 'pollsters' got it completely and historically wrong," he added.
State officials and election administrators in both Michigan and Wisconsin, as well as many other states, quickly dismissed the possibility of any fraudulent votes being included in their count, saying every vote is triple checked by the municipality, county and state.
Election observers here have attributed the last-minute flip of vote counts in favor of Biden to the record early voter turnout, noting that early votes are usually the last ones to be counted in most states and that the Democrats had heavily encouraged their supporters to vote early through mail-in ballots, resulting in early vote counts that are "heavily skewed" toward the Democrat.
More than 101 million Americans voted early in Tuesday's presidential election, accounting for more than 65 percent of about 150 million ballots estimated to have been cast, and marking the highest early voter turnout rate in the country's history.
As of noon, Biden was projected to have won 50.5 percent of some 145 million popular votes counted, while Trump won 47.7 percent.
Many believe Trump may also take it to court.
While prematurely declaring his victory in the wee hours of Wednesday, only about three hours after polling closed, Trump threatened to ask the Supreme Court to stop vote counting in states where he was leading at the time.
The Electoral College outcome is still based on unofficial vote counts that will only be certified next month after each and every state completes its own processes to double check the election results.
The winner of this week's presidential election is set to be sworn in on Jan. 20.
Should no official winner emerge by then, also leaving the vice presidency vacant, the speaker of the House of Representatives will serve as acting head of state.
The Democratic Party was projected to maintain its house majority as the result of general elections that took place simultaneously with the presidential election on Tuesday.
As of Saturday, the liberal party was projected to have won 211 seats, seven seats short of a majority, while the Republican Party is projected to have taken 197 seats.
How smooth a Biden administration will be able to run the nation will largely depend on who wins a majority of Senate seats.
Also up for grabs in Tuesday's election were 35 Senate seats, 23 of which were previously held by the Republican Party.
The Democratic Party is projected to have secured at least 48 of the 100 Senate seats so far, which marks a net gain of one seat.
It will need at least two more seats for a majority with Vice President-elect Kamala Harris set to serve as the president of the Senate with a tie-breaking vote.
The Republican Party is currently projected to have secured 47 Senate seats with vote counting still under way in four states -- Alaska, Georgia, Maine and North Carolina.
Georgia, however, is facing imminent runoff elections for its two Senate seats in early January as none of its candidates are projected to have secured a majority of votes cast as required by the state law.
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