The Republican president's resistance to acknowledging the outcome of the race has stalled the transition process.

The head of the General Services Administration, a Trump appointee, has held off on certifying Democrat Mr Biden as the winner of the election.

The certification - known as ascertainment - frees up money for the transition and clears the way for Mr Biden's team to begin putting in place the transition process at agencies.

"I just think it's an embarrassment, quite frankly," Mr Biden said on Tuesday of Mr Trump's refusal to acknowledge the election results.

The president-elect and his wife Jill Biden marked Veterans Day with a visit to the Korean War Memorial in Philadelphia.

From his Twitter account on Tuesday, Mr Trump again raised unsupported claims of "massive ballot counting abuse" and predicted he would ultimately win the race he has already lost. Mr Trump's tweets were swiftly flagged by the social media network as disputed claims about election fraud.

With the exception of weekend visits to his private golf club in northern Virginia, Trump has remained at the White House since election day and last appeared before cameras to deliver a statement six days ago.

His allies on Capitol Hill, led by Senate majority leader Mitch McConnell, have encouraged the president's baseless accusations.

They signalled they are willing to let Mr Trump spin out his election lawsuits and unsubstantiated claims of voter fraud for the next few weeks, until the states certify the elections by early December and the Electoral College meets on December 14.

Mr Trump was also joined at Arlington National Cemetery by first lady Melania Trump as well Vice President Mike Pence and his wife Karen Pence.

msn