President-elect Biden said that the Pentagon is stalling the transition, warning the US to face a security risk because of this.

"We have had a hurdle from political leadership at the Department of Defense and the Office of Management and Budget," said US President-elect Joe Biden on December 28, after he and the Vice President were elected.

"Right now we don't get all the information we need from the impending administration in key national security areas. In my opinion, this is no different from irresponsibility," Biden added.

Earlier this month, Biden's team said they were opposed by some Pentagon officials asking for information.

According to Biden, he is looking for a "clear picture" from the impending administration of US military posture around the world.

"We need to have a full vision of the budget planning that is being done at the Department of Defense and other agencies, to avoid ambiguity or gaps that our opponents can exploit."

President Trump has so far refused to recognize Biden's victory, even though the President-elect won 306 electoral votes and 7 million more popular than Trump.

The Trump administration has caused concern by upsetting the Pentagon leadership following the election, including the sacking of defense secretary Mark Esper.

Trump's last-minute disposition of loyalists in the Pentagon comes amid heightened tensions with Iran.

When taking office, Biden will inherit a series of foreign policies and national security challenges, including China, Iran and North Korea, as well as the Covid-19 pandemic raging around the globe.