Afghanistan's beleaguered president vowed on Saturday to prevent further bloodshed, as Taliban fighters closed in on Kabul after routing his armed forces over the past 10 days.

In a recorded address to the nation — his first since the Taliban launched their sweeping offensive — Ashraf Ghani said he wanted to stop the violence "as a historic mission".

"I will not let the imposed war on people cause more deaths," he said, appearing sombre and sitting before an Afghan flag.

The president gave no hint he would resign or take responsibility for the calamitous military collapse, but said the armed forces could be "remobilized" and consultations were taking place to try to help end the war.

But he offered few specifics on what his administration was planning, with government control over Afghanistan all but collapsed.

Ghani's speech came as US Marines were 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 during its 20-year occupation.

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

As the Taliban closed in on Kabul, panicked residents formed long lines outside banks, hoping to withdraw their savings. Some branches appeared to have already run of cash.

Insurgent fighters are now camped just 50 kilometres away from Kabul, with the United States and other countries scrambling to airlift their nationals out of the Afghan capital ahead of a feared all-out assault.

Heaving fighting was also reported around Mazar-i-Sharif, an isolated holdout in the north where warlord and former vice president Abdul Rashid Dostum had gathered his virulently anti-Taliban militia.

The only other cities of any significance not to be taken yet were Jalalabad, Gardez and Khost — Pashtun-dominated and unlikely to offer much resistance now.

In Kabul, US embassy staff were ordered to begin shredding and burning sensitive material, as the first American troops from a planned 3,000-strong re-deployment started arriving to secure the airport and oversee evacuations.

A host of European countries — including Britain, Germany, Denmark and Spain — all announced the withdrawal of personnel from their respective embassies on Friday.

‘Crying night and day’ 

For Kabul residents and the tens of thousands who have sought refuge there in recent weeks, the overwhelming mood was one of confusion and fear.

Muzhda, 35, a single woman who arrived in the capital with her two sisters after fleeing nearby Parwan, said she was terrified for the future.

"I am crying day and night,” she told AFP

"I have turned down marriage proposals in the past... If the Taliban come and force me to marry, I will commit suicide.”

UN Secretary General Antonio Guterres said he was "deeply disturbed” by accounts of poor treatment of women in areas seized by the Taliban, who imposed an ultra-austere brand of Islam on Afghanistan during their 1996-2001 rule.

The scale and speed of the Taliban advance have shocked Afghans and the US-led alliance that poured billions into the country after toppling the insurgents in the wake of the September 11 attacks nearly 20 years ago.

Days before a final US withdrawal ordered by President Joe Biden, individual Afghan soldiers, units and even whole divisions have surrendered, handing the Taliban even more vehicles and military hardware for their lightning advance.

‘No imminent threat’ 

Despite the frantic evacuation efforts, the Biden administration continues to insist that a complete Taliban takeover is not inevitable.

"Kabul is not right now in an imminent threat environment,” Pentagon spokesman John Kirby said on Friday, while acknowledging that Taliban fighters were "trying to isolate” the city.

The Taliban offensive has accelerated in recent days, with the capture of Herat in the north and, just hours later, the seizure of Kandahar — the group’s spiritual heartland in the south.

Asadabad, the capital of Kunar in the east, also fell on Saturday, as the Taliban tightened the noose.

On Ghani’s TV speech, Kabul-based analyst Sayed Naser Mosawi said it appeared the president was running out of options.

"The president’s message was not definitive enough to say he is willing to fight on to the end, but rather to me it sounds that he may be willing to give into some sort of settlement — if that doesn’t mean surrender,” he added.

On Saturday, helicopters flitted back and forth between Kabul’s airport and the vast US diplomatic compound in the heavily fortified Green Zone, 46 years after choppers evacuated Americans from Saigon, signalling the end of the Vietnam War.