Biden will host the president-elect in the Oval Office on Wednesday, the White House said in a brief statement on Saturday.

The meeting will bring together two bitter rivals for a display of national unity after one of the most rancorous American election campaigns in living memory.

Such moments are a tradition between the outgoing and incoming presidents, though when Trump lost his re-election bid in 2020 amid the Covid pandemic he did not invite Biden. Nor did he attend his successor’s inauguration, as is customary.

Incoming First Lady Melania Trump has also been invited to the White House to meet Jill Biden, an East Wing official told CNN, though it is unclear when that might happen.

Trump and Biden’s chat will be their first encounter since they stood almost side by side at a 9/11 memorial in New York City two months ago.

The two traded plenty of insults over the campaign, with Biden saying Trump should be locked up and appearing to call Trump supporters “garbage”, while Trump called Biden a “bad guy” and “a broken-down pile of crap”.

But on Thursday, Biden pledged to help Trump make an orderly transition back to the White House.

“Campaigns are contests of competing visions,” Biden said. “The country chooses one or the other. We accept the choice the country made. I’ve said many times you can’t love your country only when you win. You can’t love your neighbour only when you agree.”

The visual of Biden and Trump together in the White House is likely to be as striking as the one of former President Barack Obama and Trump in 2016, after Trump defeated Hillary Clinton to secure the presidency for the first time.

Harris – the Democratic candidate who Trump defeated in the 5 November election – will be required to certify his presidential victory in Congress in the new year.

Under the US Constitution, the vice-president is the president of the Senate and formally presides over the counting of electoral ballots cast in elections.

The ceremony will take place on 6 January, four years to the day since Trump supporters rioted at the Capitol as Biden’s win was being certified.

Harris became the Democratic candidate when Biden bowed to pressure within the party to step aside after his performance in a televised debate with Trump in July.

In the presidential election, Trump on Saturday completed a clean sweep of all seven swing states in US election victory, after a projected win in Arizona.

The result leaves Trump with 311 votes in the all-important US electoral college, surpassing the 270 needed to win.

In the Senate, the Republican Party has gained control with a majority of at least 52 seats. Results are yet to emerge from two states: Arizona and Pennsylvania.

In the House of Representatives, Republicans are inching towards a majority, having secured 215 seats. Nineteen races are yet to be called. A party needs 218 seats to have overall control of the chamber.