WASHINGTON — President-elect Joe Biden offered a promise for unity and healing in Saturday after securing the presidential election, and Vice President-elect Kamala Harris said “this is a country of possibilities” as she became the first Black woman to win the vice presidency.

“I’ll work with all my heart, with the confidence of the whole people, to win the confidence of all of you. And for that is what America, I believe, is about,” Biden said in his prime-time acceptance speech outside the Chase Center in Wilmington, Delaware, to a crowd of supporters sitting in and on their cars or milling about in the parking lot.

President Donald Trump has not conceded the election and learned of Biden’s Pennsylvania win while playing golf on his Virginia golf course.

This was Biden’s third run for president during a career in politics spanning over 40 years.

Biden’s speech comes after he and Harris won the battleground state of Pennsylvania, passing the 270 Electoral C ollege votes needed to win. The Associated Press and Fox News have set his number at 290 by also saying he won Arizona and Nevada. The TV networks and major newspapers also have projected him as the winner in Nevada, but not Arizona. Yet to be decided are Georgia, North Carolina and Alaska.

With over 75 million votes in the popular vote, Biden and Harris set a record for most votes for one presidential team.

In his speech, Biden focused on unity and bringing the country together in an era of divisiveness and amidst a global pandemic. He called upon supporters of Trump to join him, saying, “ I understand the disappointment tonight. I’ve lost a couple of times myself. But now, let’s give each other a chance.”

He then began to lay out his plans for the two and a half months before he takes the oath of office on Jan. 20. On Monday, he said, he will introduce his coronavirus task force to help prepare a plan for managing the pandemic.

“I will spare no effort, none, or any commitment to turn around this pandemic,” said Biden.

Biden told the crowd his vision of America as a nation “shaped by the constant battle between our better angels and our darkest impulses. And what presidents say in this battle matters. It’s time for our better angels to prevail.”

He also reiterated his campaign theme of being a president for all Americans, “Let us be the nation that we know we can. A nation united, a nation strengthened. A nation healed,” he said.

Harris spoke before Biden, claiming a victory for women across the country.

“While I may be the first woman in this office, I will not be the last, because every little girl watching tonight sees that this is a country of possibilities,” said Harris.

Democrats joined Biden and Harris in speaking of the start of a new era.

Speaker of the House Nancy Pelosi in a statement said, “Today marks the dawning of a new day of hope for America.”

2012 Republican president nominee and Utah Sen. Mitt Romney posted on Twitter, “Ann and I extend our congratulations to President-elect Joe Biden and Vice President-elect Kamala Harris. We know both of them as people of good will and admirable character. We pray that God may bless them in the days and years ahead.”

Other Republicans joined Trump in questioning the results, although there is no indication of election fraud, according to numerous election officials.

Trump is expected to file lawsuits challenging ballots in states such as Pennsylvania and Michigan.

“I will not rest until the American People have an honest vote count and that Democracy demands,” the president said in a statement.

Rep. Steve Scalise, the House minority whip, said on Twitter, “The election isn’t over until all legal votes are counted and certified. There are still serious legal challenges that have been made, and until that process is resolved, the election is not final.”

The GOP reaction shows that Biden will have a challenge in getting congressional Republicans and Democrats to work together.

“I do think the dynamic will change and Joe Biden is going to have to find some ways to work, at least legislatively, to find some common ground,” said John Fortier of the Bipartisan Policy Center.

Across the country Saturday, tens of thousands flooded the streets from Washington to New York City to Chicago in celebration of the next president.

“These last four years have been rough being in D.C.,  even being down here [at BLM Plaza]. T here’s been a lot of tension,” said Jesse Walker at a celebration in Washington. “This is what D.C. is — people coming together in the name of democracy, freedom and change.”

Christian Maccario of New York City sees the election of Biden as an awakening.

“For the last four years, myself and many of my friends and loved ones have been organizing, having plans to get more involved because we know our voice could make a difference,” said Maccario.