President Donald Trump is facing pressure to cooperate with president-elect Joe 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 Mr 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 Mr Trump, who has not publicly recognised Mr Biden's victory and has falsely claimed the election was stolen, will impede Democrats as they try to establish a government.

It comes as Mr Trump maintained his silence despite earlier threats of legal action to prove voter fraud, a stance now interpreted as less about trying to change the result as providing an off-ramp for a loss the president cannot grasp, and to keep his supporters on side.

There is little precedent in the modern era of a president erecting such transition hurdles for his successor. The stakes are especially high this year because Mr Biden will take office amid a raging pandemic, which will require a comprehensive government response.

"America's national security and economic interests depend on the federal government signalling clearly and swiftly that the United States government will respect the will of the American people and engage in a smooth and peaceful transfer of power," Jen Psaki, a Biden transition aide, tweeted on Sunday.

The advisory board of the non-partisan Center for Presidential Transition also urged the Trump administration to "immediately begin the post-election transition process and the Biden team to take full advantage of the resources available under the Presidential Transition Act".

Mr Biden, who was elected the 46th president on Saturday, is taking steps to build a government despite questions about whether Mr Trump will offer the traditional assistance.

He is focusing first on the virus, which has already killed nearly 240,000 Americans. Mr Biden will announce details on Monday of a task force that will create a blueprint to attempt to bring the pandemic under control that he plans to begin implementing after assuming the presidency on January 20.

Mr Biden was also launching agency review teams, groups of transition staffers that have access to key agencies in the current administration. They will collect and review information such as budgetary and staffing decisions, pending regulations and other work in progress from current Trump administration staff at the departments to help Mr Biden's team prepare to transition.

But that process can not begin in full until the GSA recognises Biden as president-elect. The definition of what constitutes a clear election winner for the GSA is legally murky, making next steps unclear, especially in the short term.

The GSA's leadership is supposed to act independently and in a nonpartisan manner, and at least some elements of the federal government already have begun implementing transition plans. Aviation officials, for instance, have restricted the airspace over Mr Biden's lakefront home in Wilmington, Delaware.

Meanwhile, Trump campaign aides, senior Republican officials and other allies have told AP the president's threatened legal action is more about creating a more palatable exit strategy from the White House and keeping supporters on side than it is about proving electoral wrongdoing.

Mr Trump has vowed to take legal steps while refusing to concede to Mr Biden, and is making an aggressive pitch for donors to help finance any court battle.

He and his campaign have levelled accusations of large-scale voter fraud in Pennsylvania and other states that broke for Mr Biden. So far they have been made without proof, but senior figures connected with the president say evidence of fraud is not really the point.

Aside from providing one pathway out of a defeat the president is struggling to accept, Trump aides and allies have also privately acknowledged the legal fights would at best forestall the inevitable.

Some told AP they also had deep reservations about the president's attempts to undermine faith in the vote, but most agreed he and a core group of loyalists were aiming to keep his base of supporters on his side even in defeat.

"He intends to fight," Mr Trump's economic adviser Larry Kudlow said as it was becoming clear that the president was headed for defeat.

Asked would Mr Trump ever concede, the president's long-time friend and adviser Roger Stone - whose prison sentence was commuted by Mr Trump in July - said: "I doubt it."

On Fox News Channel's Sunday Morning Futures, Trump lawyer Rudy Giuliani said two additional lawsuits were in the process of being drafted, in addition to existing litigation in Pennsylvania, and that a total of 10 suits was possible.

Lawyers could potentially argue certain vote tallies should be cast aside over fraud observed by poll watchers.

But in order to win that argument they would need evidence, not just allegations uttered so far that Republican count monitors were not allowed to see clearly enough.

Democratic poll watchers, who were also given the same access, have not raised concerns.