The German military will assist in the previously announced evacuation of German and local staff from Berlin's embassy in Kabul, Defence Minister Annegret Kramp-Karrenbauer said on Saturday.

As the Taliban edges closer to the Afghan capital, Kramp-Karrenbauer said in a statement that Germany would "mobilise the first forces as soon as possible".

"The security situation in Afghanistan continues to escalate," she said, adding that the military would help the foreign ministry in repatriating German citizens and evacuating local staff "who are in need of protection to Germany".

She declined to provide further details, adding only that "bringing those who need protection to Germany now has absolute priority".

Foreign Minister Heiko Maas had said Friday that Germany was reducing staff levels at its embassy in Kabul to an "absolute minimum" and that the evacuation would be carried out "in the coming days".

The ministry estimates its remaining staff count at the embassy in the "high double digits". 

With Afghanistan's second- and third-largest cities having fallen into Taliban hands, Kabul has effectively become a last stand for government forces who have offered little or no resistance elsewhere.

US Marines have been sent in to oversee an evacuation of embassy employees and thousands of Afghans, and their families, who fear retribution for working for the United States over the past 20 years.

A host of other NATO partners -- including Britain, Denmark and Spain -- all announced the withdrawal of personnel from their respective embassies on Friday.