Additional intelligence briefings "would be useful," Biden said, but "We don't see anything slowing us down, quite frankly."
Despite growing frustration, Biden delivered an afternoon speech on the Affordable Care Act, just hours after the Supreme Court heard arguments on its merits.
The high court ruled eight years ago to leave intact the essential components of the law known as "Obamacare," but Trump and his Republican allies are seeking to have it overturned.
If the six-three conservative court ultimately agrees with the GOP, millions of Americans could lose their healthcare coverage. While today's arguments indicate the court is unlikely to strike down the entire law, the prospect adds to the pressure on Biden to execute complicated plans to confront a series of crisis he will inherit in just 71 days.
The nation's economy is struggling as the pandemic surges and cultural divisions deepen.
Trump and his allies seemed determined to make Biden's transition as difficult as possible.
From his Twitter account, Trump again raised unsupported claims of "massive ballot counting abuse" and predicted he would ultimately win the race he has already lost.
His allies on Capitol Hill, led by Senate Majority Leader Mitch McConnell, have encouraged the President's baseless accusations.
Trump's tweets were swiftly flagged by the social media network as claims about election fraud that are disputed.
America's allies began to acknowledge what Trump would not.
French President Emmanuel Macron spoke to Biden via video conference and German Chancellor Angela Merkel and British Prime Minister Boris Johnson also congratulated Biden on his election.
"I look forward to strengthening the partnership between our countries and to working with him on our shared priorities – from tackling climate change, to promoting democracy and building back better from the pandemic," Johnson wrote on Twitter.
"Build back better" is a slogan that Biden and the British government have in common.
Biden tried to stay focused on healthcare as he prepares to take office on January 20 during the worst health crisis in more than a century. The US surpassed 10 million cases yesterday and cases are skyrocketing as the nation moves into the cold winter months.
One of Biden's chief coronavirus advisers, former Surgeon General Vivek Murthy, briefed Senate Democrats by phone at their weekly virtual lunch, according to a senior Democratic aide granted anonymity to discuss the private session.
The closed-door meeting marked the first time a Biden transition official has addressed the full Senate caucus since last week's election.
Before and after Biden's afternoon speech, he was working alongside Vice-President-elect Kamala Harris at a theater near his home in downtown Wilmington.
He is expected to quickly name a chief of staff and start considering Cabinet appointments, though those likely won't be finalised for weeks.
Complicating Biden's challenge is the Republican Party's widespread refusal to acknowledge his victory. With scant evidence, Trump and his allies are insisting that the election was stolen.
Attorney-General William Barr has authorised the Justice Department to probe unsubstantiated allegations of voter fraud. And the General Services Administration, led by a Trump-appointed administrator, Emily Murphy, has declined to formally recognise Biden as President-elect.
That designation eases cooperation between the outgoing and incoming administrations, although Murphy has not started the process and has given no guidance on when she will.
The GSA inaction could continue to deny Biden security briefings, which he received periodically before the election, as well as delaying security clearances and staffing decisions.
Senior officials in the George W. Bush administration warned that a similar delay after the closely contested 2000 presidential election caused many difficulties.
On a call with reporters, a transition official said Biden's team believes it is time for the GSA administrator to ascertain that he is President-elect. The official said legal action is "certainly a possibility" if that doesn't happen, though there are also other options being considered.
Republicans are increasingly eyeing a December deadline to give Trump time and space to exhaust his legal challenges. That's when the states face a deadline to certify results and a December 14 deadline for the Electoral College to cast its votes.
It's also about the time it took to resolve the 2000 election dispute between Republican George W. Bush and Democrat Al Gore.
"Until the Electoral College votes, anyone who is running for office can exhaust concerns," McConnell told reporters on Capitol Hill.
- AP
