Most Republicans have publicly supported Trump's effort to overturn the election results via a series of lawsuits filed in individual states, following his unfounded claims of widespread voting fraud.

Hand-count audits in more than six counties in the battleground state of Arizona, where Biden continues to lead amid ongoing vote counting, found only minor discrepancies, according to the secretary of state's office.

The audits involve hand counts of a random sampling of ballots.

Biden has been moving ahead with the work of preparing to govern and spoke with Pope Francis as his fellow Democrats in Congress blasted Republican election "shenanigans" and urged action on coronavirus.

With a few states still counting ballots, Biden has won enough battleground states to surpass the 270 electoral votes needed in the state-by-state Electoral College that determines the next president.

Biden is also winning the popular vote by more than 5.2 million votes.

A growing number of Republican senators, including John Cornyn, Ron Johnson, James Lankford, Chuck Grassley and Lindsey Graham, urged Trump's administration on Thursday to allow Biden access to presidential daily intelligence briefings.

The president-elect traditionally receives such briefings from the intelligence community to learn of threats facing the United States before taking office.

"I don't see it as a high-risk proposition. I just think it's part of the transition. And, if in fact he does win in the end, I think they need to be able to hit the ground running," Cornyn told reporters.

He refused to say, however, Biden had won.

The top House of Representatives Republican, Kevin McCarthy, opposed the idea.

"He's not president right now. I don't know if he'll be president January 20th," McCarthy said, refusing to acknowledge Trump's defeat.

A group of 150 former US officials - including some from the Trump administration - said intelligence briefings were essential to ensuring continuity of government.

The two top Democrats in Congress - House Speaker Nancy Pelosi and Senate Democratic leader Chuck Schumer - on Thursday decried Trump's refusal to engage with Biden's transition team.

The Democratic leaders also urged Republicans to join them in passing legislation to address the pandemic and buttress the battered economy.

"The Republicans should stop their shenanigans about an election President Trump has already lost and focus their attention on the immediate issue at hand - providing relief to a country living through the COVID health and economic crisis," Schumer said.

Biden, who is set to become America's second Roman Catholic president, after John F. Kennedy in the 1960s, spoke with the pope on Thursday, thanking him for his "blessing and congratulations".

Biden told the pontiff he wanted to work together on issues including caring for the poor, addressing climate change and welcoming immigrants and refugees.

Biden has focused on planning his administration, with attention expected to shift to his selections for key Cabinet posts ahead of taking office.

He named longtime adviser Ron Klain on Wednesday as White House chief of staff, his first major appointment.

Klainis expected to take a leading role in Biden's approach to the intensifying pandemic that has killed more than 242,000 Americans, with a record 142,000 new cases registered on Wednesday.

Australian Associated Press