Kabul: The Taliban called on Afghanistan's imams to urge unity when they hold their first Friday prayers since the Islamist group seized control of the country, as protests against the takeover spread to more cities on Thursday, including the capital, Kabul.

Several people were killed when Taliban militants fired on a crowd in the eastern city of Asadabad, a witness said. Another witness reported gunshots near a rally in Kabul, but they appeared to be Taliban firing into the air.

On the day Afghanistan celebrates its independence from British control in 1919, a social media video showed a crowd of men and women in Kabul waving black, red and green national flags.

"Our flag, our identity," they shouted.

At some protests elsewhere, media reported people tearing down the Taliban's white flag.

A Taliban spokesman was not immediately available for comment.

Some demonstrations were small, but combined with the desperate scramble of thousands of people seeking to flee the country they underline the challenge the Taliban face in governing.

Kabul has been largely calm, but 12 people have been killed in and around the airport, NATO and Taliban officials said.

The US military said more than 5,200 American troops were guarding Kabul airport, where multiple gates to the facility are now open, while US fighter jets were flying over the city to ensure security for the evacuation operation for diplomats and civilians including some Afghan citizens.

State Department spokesman Ned Price said 6,000 "fully processed" people were currently at the Kabul airport and would soon be boarding planes. A source told Reuters that White House officials told a congressional briefing that the United States already had evacuated 6,741 people, including 1,792 American citizens and legal permanent residents.

The Taliban swiftly conquered Afghanistan as US and other foreign troops withdrew, surprising even their own leaders and leaving power vacuums in many places.

The Taliban urged unity ahead of Friday prayers, calling on imams to persuade people not to leave Afghanistan.

Since seizing Kabul on Sunday, the Taliban have presented a more moderate face, saying they want peace, will not take revenge against old enemies and will respect the rights of women within the framework of Islamic law.

When in power from 1996-2001, they severely restricted women's rights, staged public executions and blew up ancient Buddhist statues. They were ousted in a 2001 US-led invasion.

Blacklist

A report by a Norwegian intelligence group said the Taliban had begun rounding up Afghans on a blacklist of people linked to Afghanistan's previous administration or US-led forces that supported it. Complaints by some Afghan journalists have cast doubt on assurances that independent media would be allowed.

A US lawmaker said the Taliban were using files from Afghanistan's intelligence agency, the National Directorate of Security, to identify Afghans who worked for the United States.

"They are methodically ramping up efforts to round those folks up," said Representative Jason Crow, who has been leading efforts in the US Congress to accelerate the evacuation of American-affiliated Afghans. "I've had people send me pictures of Taliban outside their apartment complexes, searching for them."

Crow voiced concern that the US government may end the evacuation operation on Aug 31, leaving more than 100,000 at-risk Afghans and family members in danger of Taliban reprisals.

Facebook, Twitter and LinkedIn said they had moved to secure the accounts of Afghan citizens to protect them from being targeted amid the Taliban's takeover.

It was unclear if the Asadabad casualties resulted from Taliban firing or from a stampede.

"Hundreds of people came out on the streets," witness Mohammed Salim said. "At first I was scared and didn't want to go, but when I saw one of my neighbours joined in, I took out the flag I have at home. Several people were killed and injured in the stampede and firing by the Taliban."

Protests flared in the city of Jalalabad and in Paktia province, also in the east.

First Vice President Amrullah Saleh, who said on Tuesday he was the "legitimate caretaker president" after President Ashraf Ghani fled, wrote on Twitter: "Salute those who carry the national flag and thus stand for dignity of the nation."

Ahmad Massoud, son of guerrilla leader Ahmad Shah Massoud, who was killed by suspected al Qaeda militants in 2001, wrote in a Washington Post op-ed that he is "ready to follow in my father's footsteps, with mujahideen fighters who are prepared to once again take on the Taliban."

Limited leverage

US President Joe Biden said the Taliban must decide if they want international recognition.

"Do they want to be recognized by the international community as being a legitimate government? I'm not sure they do," Biden said in TV interview.

White House national security adviser Jake Sullivan said in an interview with NBC News that the United States is "laser-focused" on "the potential for a terrorist attack" by a group like Islamic State amid the evacuation.

"We will get any American who wants to get to the airport and who we get in contact with who says: 'I want to get out and get on a plane,' we will make that happen," Sullivan said.

About two dozen US diplomats in Afghanistan sent an internal cable last month warning Secretary of State Antony Blinken of the potential fall of Kabul to the Taliban as US troops withdrew from the country, The Wall Street Journal reported.

G7 foreign ministers called for a united international response to prevent the crisis from worsening, in comments echoed by countries including Russia. China said the world should support, not pressure, Afghanistan.

A Taliban official said they could not be blamed for the chaos at Kabul airport. In one scene captured on social media, a small girl was hoisted over the airport's perimeter wall and handed to a US soldier.

Under a pact negotiated by former President Donald Trump's administration, the United States agreed to withdraw its forces in exchange for a Taliban guarantee not to attack departing foreign forces or let Afghanistan be used for terrorist attacks.