Defiant protesters waved Afghan flags at scattered rallies Thursday to mark the country's independence day, as a UN document suggests the Taliban are rounding up people placed on a blacklist for working with the Afghan government, or US-led forces.

As the small-scale demonstrations unfolded, the son of the nation's most famous resistance fighter vowed to take up arms against the Islamist hardliners, who are back in power after being ousted in a US-led invasion nearly 20 years ago.

Tens of thousands of people have tried to flee Afghanistan since the Taliban swept into the capital Kabul on Sunday, completing a stunning rout of government forces in a matter of days.

The United States said Thursday that it had airlifted about 7,000 people out of Kabul in the past five days -- and that the Taliban appeared to be cooperating to allow Afghan nationals registered for special US visas to reach the airport.

Small groups of Afghans waved the country's black, red and green flags in Kabul and a handful of suburbs on Thursday to celebrate the anniversary of Afghanistan's independence -- on occasion in plain sight of patrolling Taliban fighters.

"My demand from the international community, the (UN) Security Council, is that they turn their attention to Afghanistan and not allow the achievements of 20 years to be wasted," said one protester.

There were unconfirmed reports of shots fired in the northeastern city of Kunar, after Taliban fighters fired guns to disperse dozens of Afghans in Jalalabad who waved the flag Wednesday.

The Taliban have raised their own black and white banner over government buildings in Kabul.

- 'Door-to-door-visits' -

The movement's leaders have repeatedly vowed not to take revenge against their opponents, while seeking to project an image of tolerance.

But a confidential United Nations document, provided by its threat assessment consultants and seen by AFP, said the Taliban have been conducting "targeted door-to-door visits" searching for people they want to arrest.

Most at risk are people who had central roles in the Afghan military, police and intelligence units, but those who worked for US and NATO forces were also included on "priority lists", the report said.

Militants are also screening individuals on the way to Kabul airport and have set up checkpoints in major cities, including the capital and Jalalabad, the document alleges.

Memories of the Taliban's brutal regime of the 1990s -- which saw music and television banned, people stoned to death and women confined to their homes -- have caused panic about what lies ahead for Afghans.

In the Panjshir Valley northeast of Kabul -- the country's last holdout -- Ahmad Massoud, the son of Afghanistan's most famed anti-Taliban fighter Ahmed Shah Massoud, said he was "ready to follow in his father's footsteps".

"But we need more weapons, more ammunition and more supplies," Massoud said. 

- 'A situation worse than death' -

The United States, which successfully toppled the Taliban's first regime in 2001 following the September 11 attacks, was just weeks away from completing its military withdrawal when the militants seized power. 

Now, more than 5,200 US troops are back to facilitate the airlift of American citizens and Afghan allies who worked with American forces.

Chaos erupted at the airport this week, as frantic Afghans searched for a way to leave the country. 

An Afghan sports federation announced a footballer for the national youth team had died after falling from a US plane he desperately clung to as it took off. 

The Group of Seven and the heads of several UN agencies echoed US calls for the Taliban to allow safe passage for those Afghans trying to leave, but Pentagon spokesman John Kirby said the situation was improving.

"We have indications this morning that that process is working," he told reporters.

State Department spokesman Ned Price later said there had been "productive conversations" with the Taliban "about the need and the imperative of ensuring safe passage".

Unconfirmed reports say several people have been killed as US forces and the Taliban -- separated by an unofficial no-man's land -- struggle to contain the desperate crowds.

"I went to the airport with my kids and family... the Taliban and Americans were shooting," said one man, who until recently had worked for a foreign non-governmental organisation.

"Despite that, people were moving forward just because they knew a situation worse than death awaited them outside the airport."

- 'The system has been changed' -

Many are struggling to believe Taliban pledges of a "positively different" regime this time around.

An Afghan woman journalist made a desperate social media plea Thursday after she was barred from entering the TV station where she worked.

"The male employees... were allowed to enter the office, but I was told that I couldn't continue my duty because the system has been changed," news anchor Shabnam Dawran said, adding: "Our lives are under threat."

The Taliban are edging towards establishing a government, with co-founder Abdul Ghani Baradar returning from exile and other senior figures meeting ex-president Hamid Karzai and other former government officials.

The group said it wants "good diplomatic relations" with all countries, but will not accept any encroachment on its religious principles. 

"We will not submit to the pressure of anyone," it said, in a statement published by SITE monitoring group. 

$6m for Afghan evacuation

A GoFundMe campaign to raise money for the evacuation of 300 vulnerable Afghans fleeing the Taliban has raised over $6 million, according to figures published Thursday.

The creator of the fundraising page, New York-based Tommy Marcus, asked for funds to organize flights out of the country for Afghans who risk being targeted by the Taliban.

They include men and women who worked as human rights lawyers, LGBTQ activists, journalists, government liaisons and others, "all of whom are at imminent risk of being executed by the Taliban, along with their families," the page said.

Marcus said he was working with aid groups, veterans and activists on the ground in Kabul to plan the rescue operation.

Since its launch earlier this week, the campaign has received donations from over 106,000 people, with contributions ranging from $1 to $20,000, collecting $5 million in the space of just one day.

"If these people do not get rescued as soon as possible, neither they nor their family will make it through the month," the page said.

Neither GoFundMe nor Marcus responded to request for comment.

Thousands of Afghans rushed to Kabul airport in a desperate attempt to flee the country after the Taliban takeover of the capital on Sunday, with several people dying in the melee.

Western governments have been evacuating thousands of their citizens as well as Afghan civilians who have worked for them, but the evacuations have been marked by chaos. 

Memories are still fresh among Afghans of the Taliban's brutal rule from 1996 to 2001, during which girls could not go to school, women were barred from working in jobs that would put them in contact with men, and people were stoned to death.