Joe Biden has stopped short of officially declaring victory in the US election but said he is confident he is ultimately going to win the race to the White House.

The Democratic candidate took the lead in the key battleground states of Pennsylvania and Georgia on Friday, with forecasters putting him just one state from victory as officials continue counting votes.

Speaking in Wilmington, Delaware, just before 11pm on Friday local time, the former vice-president said although he did not have a final declaration, “the numbers tell us a clear and convincing story”.

Mr Biden said: “We’re going to win this race, just look at what has happened since yesterday.

“24 hours (ago), we were behind in Georgia, now we’re ahead, and we’re going to win that state. 24 hours ago, we were behind in Pennsylvania and we are going to win Pennsylvania. Now we’re ahead, we’re winning in Arizona, winning in Nevada, in fact our lead just doubled in Nevada.

“We’re on track to 300 electoral college votes, and look at the national numbers. We’re going to win this race with a clear majority with a nation behind us.”

Mr Biden added: “We’ve gotten over 74 million votes, that’s more than any presidential ticket has ever gotten in the history of the United States of America.

“And our vote total is still growing. We’re beating Donald Trump by over four million votes and that’s a margin that’s still growing as well.”

In a sign of his confidence in the eventual result, Mr Biden said he and vice-presidential candidate Kamala Harris had already got to work on developing initial steps to address the country’s ongoing battle with the coronavirus pandemic.

He said: “Daily cases are skyrocketing, and it is now believed that we could see spikes as high as 200,000 cases in a single day. The death toll is approaching 240,000 lives lost to this virus. That’s 240,000 empty chairs at the kitchen and dinner tables across America.

“We’ll never be able to measure all the pain, the loss, and the suffering so many families have experienced. I know how it feels to lose someone you love, and I want them to know they’re not alone. Our hearts break with you.

“And I want everyone to know that on day one, we are going to put our plan to control this virus into action.”

Mr Biden also called on his supporters to be patient as votes continue to be counted, urging them to “never forget the tallies aren’t just numbers, they represent votes and voters, men and women who exercised their fundamental right to have their voice heard”.

On Friday, Mr Biden overhauled Mr Trump’s leads by more than 9,000 votes in Pennsylvania and 4,235 in Georgia, where a recount has been ordered.

Counters could also be redeployed in Pennsylvania where a recount is expected under state law if there is less than half a percentage point between the two candidates.

Mr Biden finished his speech with an appeal for calm along with a veiled response to Mr Trump’s legal challenges, which the president has launched to improve his chances of re-election amid baseless allegations of fraud.

Mr Biden said: “I know tensions can be high after a tough election like the one we’ve had. But we need to remain calm. Patient. And let the process work out as we count all the votes.”

Earlier, Mr Trump signalled he would not go quietly from the Oval Office, tweeting: “Joe Biden should not wrongfully claim the office of the president. I could make that claim also. Legal proceedings are just now beginning!

“I had such a big lead in all of these states late into election night, only to see the leads miraculously disappear as the days went by. Perhaps these leads will return as our legal proceedings move forward!”

The Biden campaign was forthright in its reply to an earlier outburst by Mr Trump, in which he made unsubstantiated claims about “illegal ballots” in the election.

“As we said on July 19, the American people will decide this election,” the campaign said in a statement.

“And the United States Government is perfectly capable of escorting trespassers out of the White House.”

Prime Minister Boris Johnson continued to say he has “every confidence” in the checks and balances of the American constitution and said he would “work closely with whoever is the president” but declined to comment further.

The winner needs to collect 270 electoral college votes by winning states.

Victory in Pennsylvania would hand the presidency to Mr Biden with its 20 votes but Georgia, with 16 electoral votes, is a more complicated scenario.

Not everyone agrees that Mr Biden has beyond all probability won in Arizona, and without that Georgia would leave him one vote short of overall victory.

He has secured victories in the battleground states of Wisconsin and Michigan, but Nevada and North Carolina also remain too close to call after Tuesday’s election.

The Trump campaign requested a recount in Wisconsin and filed lawsuits in Pennsylvania, Michigan and Georgia.

But judges in Michigan and Georgia dismissed the actions launched by the Trump campaign. Additional legal action was also expected in Nevada, the campaign indicated.

The Associated Press news agency, which PA relies on to call states, has projected Mr Biden as winning Arizona and its 11 electoral college votes.

That looks likely as he has a strong lead with more than 90% of the votes tallied but Mr Trump’s campaign disagrees and other news organisations are not so certain.

The appearance of Mr Biden coming back from behind is an artificial one. Many of the outstanding ballots are postal votes and absentee ballots which are being added to the tally later than their in-person counterparts.