Senior International Correspondent John Irvine reports from Kabul, where the Taliban can be seen patrolling the streets
The Taliban says it is holding talks aimed at forming an “open, inclusive Islamic government” in Afghanistan, after the militants captured almost all of the country.
Earlier on Sunday, an official from the militant group said it is set to declare the Islamic Emirate of Afghanistan from the presidential palace in the capital, Kabul.
The Islamic Emirate of Afghanistan was the name of the country under the Taliban government ousted by US-led forces after the September 11, 2001, terror attacks.
However, these plans appear to currently be on hold, with no announcement other than the talks confirmed.
Images obtained by Al Jazeera showed Taliban fighters inside the presidential palace.
It comes just hours after President Ashraf Ghani fled the country.
Mr Ghani left along with his National Security Adviser Hamdullah Mohib and a second close associate, two officials said.
A senior Afghan Interior Ministry official said Mr Ghani had left for Tajikistan. Asked for comment, the president's office said it "cannot say anything about Ashraf Ghani's movements for security reasons".
A representative of the Taliban said the group was checking on Mr Ghani's whereabouts.
Scenes from Kabul show Taliban leaders in the capital getting a warm welcome, but it is not known how many in the crowd are genuine supporters and how many were frightened into showing adulation.
A Taliban leader seen addressing the crowd told them Kabul had been conquered and that under Sharia law, everyone's health and wealth would be secured.
With the Taliban sweeping across the country, Afghans and foreigners alike have been racing for the exit, signalling the end of a 20-year Western experiment aimed at remaking the country.
Kabul's international airport has now closed to commercial flights amid reports of gunfire. Military flights are continuing.
Civilians fearing that the Taliban could reimpose the kind of brutal rule that all but eliminated women’s rights rushed to leave the country, lining up at cash machines to withdraw their life savings, with some ATMs stopping distributing cash.
Workers have fled government offices and helicopters have been landing near the US Embassy in Kabul to evacuate staff. Smoke could be seen rising from the compound as staff destroyed important documents. Several other Western missions are pulling their staff out.
The number of British diplomatic staff in Afghanistan has been reduced although the ambassador remains in Kabul, the Foreign, Commonwealth and Development Office has said.
A spokesperson said that efforts were continuing to enable remaining British nationals to leave the country.
"We have reduced our diplomatic presence in response to the situation on the ground, but our ambassador remains in Kabul and UK Government staff continue to work to provide assistance to British nationals and to our Afghan staff," the spokesperson said.
"We are doing all we can to enable remaining British nationals, who want to leave Afghanistan, to do so."
A defence official said the US was sending in another 1,000 troops to Afghanistan to aid with the evacuations.
It raises the US deployment to around 6,000, far short of the 110,000 troops the US had stationed in Afghanistan at the height of the offensive.
It comes just one day after US President Joe Biden announced another 1,000 troops would be deployed.
"People didn't see this coming," says ITV News Global Security Editor Rohit Kachroo, adding that just a few days ago the US intelligence community predicted the fall of Kabul would take place in November, not mid-August.
In a stunning rout, the Taliban seized nearly all of Afghanistan in just over a week, despite the billions of dollars spent by the US and Nato over nearly two decades to build up Afghan security forces.
Just days earlier, an American military assessment estimated it would be a month before the capital would come under insurgent pressure.
Instead, the Taliban swiftly defeated, co-opted or sent Afghan security forces fleeing from wide swaths of the country, even though they had some air support from the US military.
ITV News Senior International Correspondent John Irvine is currently locked in at a hotel in Kabul. This is what he has said about the situation in the city:
American negotiators have been urging the Taliban to go easy and to stop their rampage but they're not quitting while they are ahead, and they've been coming into Kabul from all sides this morning and this afternoon.
The streets around this hotel, which is under lockdown, are reasonably quiet as people try to assess just how dangerous it is to be out and about.
Above us, we've been watching American helicopters and American apaches have been putting out defensive chaff which suggest they believe the Taliban are now in the centre of Kabul. They feel threatened by the Islamists. They know the weaponry they've picked up along the way here, including anti-aircraft missiles.
The city is in a very strange place.
President Joe Biden has been urging the Afghan army to fight, but it simply hasn't.
The Americans and the British have spent billions trying to train and equip the army, but that policy has been an abject failure and allowed for the Islamists to take over pretty much all of Afghanistan in just over a week.
Taliban spokesman Suhail Shaheen earlier on Sunday told Qatar’s Al-Jazeera English satellite news channel that the insurgents are “awaiting a peaceful transfer of Kabul city”. He declined to offer specifics on any possible negotiations between his forces and the government.
But when pressed on what kind of agreement the Taliban wanted, Shaheen acknowledged that they were seeking an unconditional surrender by the central government.
Prior to his departure, Mr Ghani appeared increasingly isolated.
Warlords he negotiated with just days earlier surrendered to the Taliban or fled, leaving him without a military option. Negotiations in Doha, Qatar, the site of a Taliban office, had failed to stop the insurgents’ advance.
The insurgents told residents of the capital that their fighters would not enter people’s homes or interfere with businesses. They also said they would offer an “amnesty” to those who worked with the Afghan government or foreign forces.
“No one’s life, property and dignity will be harmed and the lives of the citizens of Kabul will not be at risk,” the insurgents said in a statement.
But there have been reports of revenge killings and other brutal tactics in areas of the country the Taliban have seized in recent days.
One young woman who lives in Herat province expressed despair at the prospect of a Taliban government.
“Having devoted my life to the fight for the rights of women, it is very difficult to accept that all my efforts will be buried under the ground,” said the 25-year-old who works for a non-governmental organisation. She spoke on condition of anonymity because she feared for her safety.
The militants seized Kabul just hours after they took control of the nearby city of Jalalabad — which had been the last major city besides the capital not in Taliban hands.
Earlier in the day, militants posted photos online showing them in the governor’s office in Jalalabad, the capital of Nangarhar province.
Abrarullah Murad, a lawmaker from the province told the Associated Press that the insurgents seized the city after elders negotiated the fall of the government there. Mr Murad said there was no fighting as the city surrendered.
The militants also took Maidan Shar, the capital of Maidan Wardak, on Sunday, Afghan lawmaker Hamida Akbari and the Taliban said.
Another provincial capital in Khost also fell to the insurgents, said a provincial council member who spoke on condition of anonymity for fear of reprisals. Afghan officials said the capitals of Kapisa and Parwan provinces also fell.
The militants also took the land border at Torkham, the last not in their control, on Sunday. Pakistan’s Interior Minister Sheikh Rashid Ahmed told local broadcaster Geo TV that Pakistan halted cross-border traffic there after the militants seized it.
Later, Afghan forces at Bagram air base, home to a prison housing 5,000 inmates, surrendered to the Taliban, according to Bagram district chief Darwaish Raufi. The prison at the former US base held both Taliban and Islamic State group fighters.
Meanwhile, Boris Johnson has agreed to recall Parliament to debate the Taliban’s seizure of Afghanistan.
Speaking after after chairing an emergency Cobra meeting to discuss the Taliban’s seizure of Afghanistan, the prime minister said Afghanistan must not "become a breeding ground for terror" and the west must work together to ensure this.
Tory MP Tobias Ellwood, chair of the Commons Defence Committee, has urged Mr Johnson to convene an emergency conference of “like-minded nations” to see what could be done.
He said: “I plead with the prime minister to think again. We have an ever-shrinking window of opportunity to recognise where this country is going as a failed state,” he told Times Radio.
“We can turn this around but it requires political will and courage. This is our moment to step forward...
“We could prevent this, otherwise history will judge us very, very harshly in not steeping in when we could do and allowing the state to fail.”
Mr Ellwood said the UK should deploy the Royal Navy’s HMS Queen Elizabeth carrier strike group to Afghanistan, to provide air support.