BRUSSELS: The fall of Kabul to the Taliban and the chaotic international evacuation effort shows that Europe needs to develop its own military capacity independent of the United States, EU foreign policy chief Josep Borrell argues.

In an interview with AFP, Borrell said European powers would struggle to evacuate their citizens and Afghan allies before the United States ends its operation at Kabul airport - perhaps as early as August 31.

Several US allies have asked Washington to delay this departure, as NATO secretary general Jens Stoltenberg confirmed on Friday, as without the protection of the 6,000 US troops deployed at the airport, European operations may have to cease.

The shocking collapse of the Western-backed Afghan government, the chaotic scenes at the airport and fears that a new generation of Afghan refugees may attempt to head to Europe have revived talk of Europe developing the means to act on its own.

The EU diplomatic mission in Kabul counts 400 Afghan staff and family members that would be eligible to emigrate to Europe - but only 150 have been able to leave so far and some of the planes dispatched by EU militaries are flying out half-empty.

A third of the passengers on on a flight that arrived in Spain on Saturday were Americans, Borrell told AFP.

"The problem is access to the airport - the US checks and security measures are very strong" and were preventing the passage of Afghan staff, Borrell said, adding that Brussels had asked Washington to show "more flexibility".