Video report by ITV News Washington Correspondent Robert Moore
Joe Biden has said he is confident of winning the US presidency but held back from declaring a win as he secured the key battleground states of Michigan and Wisconsin.
Mr Biden, who has received more than 71,000,000 votes, the most votes in US history, was joined by his running mate Kamala Harris at the news conference, as he edges closer to the 270 electoral votes needed to win the presidency.
"I will govern as an American president," Mr Biden said, before adding: "There will be no red states and blue states when we win. Just the United States of America."
Speaking in Delaware, as votes continued to be counted for several US states, Mr Biden said: "It's clear that we're winning enough states to reach 270 electoral votes needed to win the presidency."
Mr Biden said the American "people would not be silenced" and urged for unity in what he described as a "difficult campaign".
Watch presidential hopeful Joe Biden speaking in Delaware:
Mr Biden added: "Now, every vote must be counted. Nobody is going to take our democracy from us, not now, not ever.
"We the people will not be silenced, we the people will not be bullied, we the people will not surrender, my friends I am confident we will emerge victorious."
After a divisive campaign, Mr Biden urged the American people to "unite, heal and come together as a nation".
He said: "Once this is behind us, it is time to lower the temperature, to see each other again, to listen to each other again, to respect and care for one another.
"I will work as hard for those who didn't vote for me as those who did. There will be no blue states or red states when we win, just the United States of America."
When could a winner be announced?
Joe Biden and Donald Trump are on 253 and 213 electoral college votes respectively, with the majority of result projections already called.
The winner needs to secure 270 electoral college votes to win the presidency - the remaining states yet to be announced each carry a different amount of those votes.
Projections for six states are yet to be made - including the four remaining key battleground states of Pennsylvania, Arizona, North Carolina and Georgia.
Of these states, Pennsylvania is worth 20, Arizona is worth 11, North Carolina is worth 15 and Georgia is worth 16 electoral college votes
Nevada, currently unannounced, is worth six electoral college votes but has warned it will not have further results updates until Thursday 5pm GMT.
If Biden is able to hold Nevada for the Democrats and turn Arizona from blue to red, that would be enough for him to secure the necessary 270 electoral college votes needed to become the 46th president of the United States. He also has other routes to the White House.
Authorities in Pennsylvania have said the outcome there may be delayed until Thursday, possibly even Friday, as election officials continue to count ballots.
Until either candidate has enough 270 electoral college votes, the result remains unclear. Even after one of the candidates reaches 270, there could be recounts in states which are close and possibly even a legal battle in the Supreme Court.
Watch ITV News Washington Editor Robert Moore's live analysis:
Mr Biden's comments came as Mr Trump's campaign announced it is filing a lawsuit to stop vote counting in Georgia, a campaign official said.
Trump Deputy Campaign Manager Justin Clark said in a statement: "A Republican poll observer in Georgia witnessed 53 late absentee ballots illegally added to a stack of on-time absentee ballots in Chatham County.
"We will not allow Democrat election officials to steal this election from President Trump with late, illegal ballots."
The Trump Campaign is also asking the Supreme Court to intervene to stop the count in battleground state Pennsylvania, will request a recount for Wisconsin and has instigated legal action over ballot counting in Michigan.
Mr Trump’s campaign manager Bill Stepien claimed the team “had not been provided with meaningful access to numerous counting locations to observe the opening of ballots and the counting process, as guaranteed by Michigan law”.
Before the projected win in Michigan, Mr Stepien said in a statement: "We have filed suit today in the Michigan Court of Claims to halt counting until meaningful access has been granted.
"We also demand to review those ballots which were opened and counted while we did not have meaningful access. President Trump is committed to ensuring that all legal votes are counted in Michigan and everywhere else."
On Wisconsin, Mr Stepien said in a statement: "The president is well within the threshold to request a recount and we will immediately do so."
The Trump campaign will seek to intervene in an ongoing case involving the deadline for receiving mail-in ballots.
Deputy campaign manager Justin Clark said in a statement the campaign is “suing to stop Democrat election officials from hiding the ballot counting and processing from our Republican poll observers”.
He said the campaign wants "to temporarily halt counting until there is meaningful transparency and Republicans can ensure all counting is done above board and by the law".
Both candidates have claimed to be winning since votes ended on Tuesday, with the president making the unsubstantiated assertion that there is a "fraud on the American nation" around the vote.
Mr Trump has said in a series of tweets, that have been marked as 'misleading' by the social media company, accusing the Democrats of cheating and unfounded reports of ballots being dumped.
Eric Trump repeated the claims and said that they have "declared victory" in Pennsylvania.
He said: "The Democrats know that the only way to win this election is to cheat in Pennsylvania.
"This is fraud. They are trying to make a mockery of the election of this country."
In a statement on Wednesday morning, Mr Trump claimed to have won the election and called for "all voting to stop" despite ballots still being counted and the outcome unknown still in nine of the 50 states.
Responding to Mr Trump's White House statement, the Biden campaign described the president's statement as "outrageous, unprecedented, and incorrect".
Later on Wednesday, the president tweeted that he had been leading in "many key states" including Democrat strongholds overnight - before referring to "surprise ballot dumps" that, he claims with no supporting evidence, caused his lead to "magically disappear" - something he called "very strange".
Watch ITV News' Emma Murphy's analysis of Joe Biden's speech:
Speaking at the White House, Mr Trump said: "This is a fraud on the American public, this is an embarrassment to our country. "
Mr Trump said: "We were getting ready to win this election - frankly we did win this election. So our goal now is to ensure the integrity for the good of this nation. This is a very big moment.
"This is a major fraud on our nation. We want the law to be used in a proper manner. So we will be going to the US Supreme Court, we want all voting to stop."
Responding to the threat of legal action, the Biden Campaign issued a statement saying: "If the president makes good on his threat to go to court [...] we have legal teams standing by ready to deploy to resist that effort."
Donald Trump claims 'fraud' and says 'we did win this election'
Listen to ITV News US election podcast, Will Trump Win? with reaction and analysis on election night and Trump's comments