The Ministry of Defence have confirmed that seven Afghan civilians were killed in the chaotic scenes outside Kabul airport.
"Our sincere thoughts are with the families of the seven Afghan civilians who have sadly died in crowds in Kabul," said a spokesman.
"Conditions on the ground remain extremely challenging but we are doing everything we can to manage the situation as safely and securely as possible."
This comes as Defence Secretary Ben Wallace says "no nation will be able to get everyone out".
Writing in the Mail on Sunday, he said: "If the US timetable remains, we have no time to lose to get the majority of the people waiting out.
"Perhaps the Americans will be permitted to stay longer, and they will have our complete support if they do."
He added that the UK was looking at "ways to keep a presence in the country after the military are gone" as there was still a lot to do to "ensure conditions are right" but gave no further details.
The Defence Secretary's words were echoed by Armed Forces Minister James Heappey, who, when asked whether the Government is confident it can get all British nationals out of Afghanistan, told reporters: "We can't confidently say that and everybody has been clear, unfortunately, in answering those questions over the last few days that that is the case.
"What I can tell you is that every single day more capacity is being made available for the number of planes going backwards and forwards between the UAE (United Arab Emirates) and Kabul.
"Other nations are putting themselves into the UK effort because they recognise that ours is one of the best co-ordinated and best commanded – and that is increasing capacity. And of course, flow is improving.
"Now, that could change – the crowds could swell again and everything could become as desperate as you saw yesterday – but for as long as that is not the case, as long as the marshalling continues to be as it is today, we will be able to process people in good volumes and that will allow us to ensure that the absolute minimum number of people are left behind, if any at all."
He went on: "But absolutely nobody, sadly, can sit on TV camera, as much as we want to, and say that we will be able to get everybody out.
"The hard reality of complex, chaotic, dangerous situations like this is that that simply may not be the case."
The Prime Minister has also announced that he will convene G7 leaders on Tuesday for "urgent talks on the situation in Afghanistan".
He said: "It is vital that the international community works together to ensure safe evacuations, prevent a humanitarian crisis and support the Afghan people to secure the gains of the last 20 years."
The relationship on either side of the Atlantic could be feeling a strain.
Former Prime Minister Tony Blair, who was in Downing Street when Britain sent troops into Afghanistan 20 years ago in the wake of 9/11, has accused US President Biden of deciding to pull out of the central Asian country with "little or no consultation".
Mr Blair branded the move "imbecilic".
Meanwhile, Foreign Secretary Dominic Raab, who has come under increasing pressure to resign after it was revealed he was on the Greek island of Crete as the Taliban took control of Afghanistan, is reportedly seeking to speak to his opposite number, US Secretary of State Antony Blinken.
According to the Sunday Times, he is keen to discuss the prospect of the US extending their end-of-the-month deadline.
The MOD has confirmed that the Operation Pitting evacuation mission has repatriated nearly 4,000 people from Afghanistan since 13 August.
In the Mail on Sunday, Ben Wallace praised the 1,000 UK service personnel situated in Afghanistan.
"The Parachute Regiment at the airport are dealing with unimaginable challenges. Public order, overcrowding, searing heat and desperate people," he said.
"Soldiers trained for war are instead holding babies and co-ordinating crowds."
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Cover image: Troops at Kabul airport (Picture: MOD).