US President Joe Biden has not spoken with any of his fellow world leaders since Kabul fell to the Taliban, the White House said on Tuesday.

"He has not yet spoken with any other world leaders," National Security Advisor Jake Sullivan told reporters.

"Myself, Secretary (Antony) Blinken, several other senior members of the team have been engaged on a regular basis with foreign counterparts and we intend to do so in the coming days," he added.

The sudden scramble to get foreigners out of Afghanistan after the Taliban victory caught the White House unprepared and sparked concern in Europe over a potential for mass refugee arrivals.

White House spokeswoman Jen Psaki told reporters that the administration's focus was currently on the tense evacuation process for thousands of Americans and Afghan allies from Kabul, which is under full Taliban control.

That means "coordination at a lower level than leaders and heads of state," she said.

"If there is a benefit in the president picking up the phone and calling world leaders, he will certainly do that and I expect he'll do that in the coming days."