Defence Secretary Ben Wallace has said it is “unlikely” the 31 August deadline to pull troops out of Afghanistan will be extended as it gets “more and more dangerous”.
Speaking to Sky News, he said: “As we get closer it’s correct to say the security risk goes up, it gets more and more dangerous.
“Add-on groups and other terrorist groups like ISIS would like to be seen taking credit, would like to be seen chasing the West out of Afghanistan – that will feed their narrative and ambitions.
“The Taliban control the outer ring outside the airport, which makes it harder for ISIS to get through and they’re certainly no friends of the Taliban.
“But we’re very vulnerable should a terrorist choose to do something.”
Boris Johnson is joining a G7 leaders’ summit online today where he will call on US President Joe Biden to extend the 31 August deadline for pulling all US troops out of Afghanistan.
The prime minister tweeted this morning that he will ask “our friends and allies to stand by the Afghan people and step up support for refugees and humanitarian aid”.
“The Taliban will be judged by their deeds and not their words,” he added.
But the Taliban told Sky News the end of the month was a “red line” and there would be “consequences” if that was extended.
On whether Mr Biden will extend that deadline, Mr Wallace said: “I think it’s unlikely, not only because of what the Taliban has said but also the public statement from President Biden.
“It’s worth us all trying, and we will.”
On Monday, Mr Wallace said the UK’s evacuation effort is “down to hours now, not weeks”.
Mr Wallace added that over the past 24 hours, the UK has evacuated more than 2,000 people – an extra 700 people compared with the previous day.
He said the UK has changed its tactics for getting out of Afghanistan entirely, so it can be done quicker.
“Every hour we can squash the military evacuation is an hour we can use to carry out the human evacuation,” he added.
Since 14 August, a day after the Taliban took Kabul, 8,600 British nationals and Afghans who worked for the British over the past 20 years, as well as their families, have been flown out of the capital.
The defence secretary said there are enough aircraft and there is a steady flow of them coming into the airport, but the challenge is getting people to the airport and processing them as they have to get through Taliban checkpoints between the city and the airport.
He added that there are about 3,000 people outside the British and US control gates and nearly 15,000 people in total outside the airport.
Many Afghans who worked for the British have been unable to get to the airport.
On Monday, armed forces minister James Heappey told Sky News there will be a “second phase” in which eligible Afghans will be able to register for the UK’s Afghan Relocations and Assistance Policy (ARAP) at a refugee handling centre or embassies in the region.