Donald Trump has launched another attack on the press as he still refuses to accept defeat in the election.

Tweeting on Sunday evening, the president wrote: “Since when does the Lamestream Media call who our next president will be? We have all learned a lot in the last two weeks!”

In an almost-stirring show of unity, first lady Melania Trump has broken her silence and echoed her husband’s false allegations of voter fraud. 

“The American people deserve fair elections. Every legal — not illegal — vote should be counted. We must protect our democracy with complete transparency,” she tweeted on Sunday.

After nearly four days of counting, a victory was yielded for Democratic candidate Joe Biden on Saturday.

With Trump still insisting the race is not over – his adult sons, Donald Jr and Eric, have also urged their father to keep fighting and challenged Republicans to stand with them.

Meanwhile, the White House released a terse statement on Saturday saying that the president “will accept the results of a free and fair election” and that the administration “is following all statutory requirements”.

Still, there are concerns that Trump’s rhetoric will inflame tensions in a nation that was already bitterly divided before the election.

The Biden campaign made clear its patience had limits.

“As we said on July 19, the American people will decide this election,” Biden’s spokesman Andrew Bates said on Friday.

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

The Nelson Mandela foundation is the latest group to urge Trump to concede, calling for him to “embrace the democratic process, support the transition, and begin contributing to the healing of a deeply fractured society”.

“As Nelson Mandela often used to say, a good leader knows when to step down. And how to do so appropriately. It’s not too late for Trump to embrace dignity, for himself and for others,” a statement said.

Trump is not expected to ever formally concede, according to people close to him, but is likely to grudgingly vacate the White House at the end of his term.

At this point, the president is also facing pressure to cooperate with Biden’s team to ensure a smooth transfer of power when the new administration takes office in January.

The General Services Administration (GSA) is tasked with formally recognising Biden as president-elect, which begins the transition. But the agency’s Trump-appointed administrator, Emily Murphy, has not started the process and has given no guidance on when she will do so.

That lack of clarity is fuelling questions about whether Trump will impede democrats as they try to establish a government.

This comes after turnout in the US election has hit a 50-year high and eclipsed the record set in Barack Obama’s triumph in 2008, in what analysts are calling an extraordinary engagement in what amounted to a referendum on Trump’s leadership.