The US has warned its citizens to avoid Kabul airport amid continued chaos outside the terminal.
A security alert issued on Saturday told US citizens to stay away due to “potential security threats outside the gates”.
Only those individually told to make the journey by a US government representative should do so, it said.
The advice comes as thousands try to escape from Afghanistan via the airport following the Taliban takeover.
The militant group swept across the country and captured the capital Kabul on 15 August. Since then, tens of thousands of Afghans – as well as foreign nationals – have headed to the airport in a bid to flee the country.
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Crowds have been gathering daily, hoping to be allowed onto a flight. Those who work with the US and its allies, as well as people who have campaigned on issues like human rights, fear they may face reprisals at the hands of the Taliban if they are unable to leave.
What exactly has been happening at the airport gates on Saturday remains unclear.
However, Sky News’ chief correspondent Stuart Ramsay said that people at the front of the crowd of thousands were being “crushed to death”, with British soldiers pulling those in danger from the throng.
He has described it as “the worst day by far”, and said they believed people had died at the scene.
In a briefing on Saturday, the US Department of Defense said 17,000 people have been flown out of the airport, including some 2,500 US citizens.
An official said a “small number” of Americans and Afghans the US want to evacuate have faced harassment. In some cases, they have been beaten on their way to the airport.
However, the Pentagon gave no further details about why it had issued the warning about the airport, saying it was simply a “prudent notification”.
Other countries have also warned about the situation on the ground.
Germany’s government issued a statement saying the airport remains “extremely dangerous and access to the airport is often not possible”, while the Swiss foreign ministry announced the security situation had “deteriorated significantly in the last few hours” and postponed a chartered evacuation flight from Kabul.
US forces are currently controlling the international airport. They are helping to evacuate their own citizens and those of other countries, including Afghans who worked with Western forces and fear for their safety under the Taliban.
But the US has set a withdrawal date of 31 August for their troops, and it is unclear what will happen after this date.
Nato Secretary General Jens Stoltenberg says several countries from the alliance have proposed that Kabul airport remain open for evacuations beyond 31 August to allow them to get more people out.
The BBC understands the UK is one of these countries, and is requesting an extension of a few days.
Some fear they will not be able to evacuate all their citizens, or all the Afghans they believe to be in danger, as they struggle to process all those queueing at the airport and to step up the number of evacuation flights.
On Friday US President Joe Biden vowed that “any American who wants to come home, we will get you home”. But he admitted the evacuation was “not without risk of loss”, declaring it “one of the largest, most difficult airlifts in history”.
The Taliban meanwhile are trying to consolidate their control over Afghanistan.
Mullah Abdul Ghani Baradar, the group’s co-founder, has now arrived in Kabul and is set to join talks on establishing a new government for the country.
He is the most senior Taliban leader now in the country and is likely to become a leading figure in any Taliban-led government.
Mr Baradar signed an agreement with the US in 2020, in which the US agreed to withdraw all its forces from Afghanistan.