media captionDominic Raab sets out the numbers of people expected to arrive in the UK from Afghanistan
The UK is to send a further 200 troops to Kabul after the Taliban seized control of the Afghan capital.
A total of about 900 UK troops will patrol Kabul's airport amid chaotic scenes on the runway, as part of efforts to secure evacuation flights.
Foreign Secretary Dominic Raab confirmed 350 more UK nationals and Afghans who worked with UK troops would be evacuated in "the days that come".
He said the UK was considering how many Afghan refugees it would take in.
Mr Raab said the situation was "not what we wanted, but we have to deal with the new reality".
He said 289 Afghans who worked with the UK had come to the UK "over the last week"
And on Monday evening, the Home Office said the UK had in total admitted more than 3,300 Afghan interpreters, staff and their families to the UK for resettlement.
The Home Office said "it will be guided by the capacity of local authorities" when deciding how many Afghan refugees to allow to settle in the UK after the Taliban seized power.
- Ten days that shook Afghanistan
- Who are the Taliban?
- Live updates: Chaos at Kabul airport
Chaotic scenes at Kabul airport saw a number of people die on Monday, prompting all flights to be halted.
The Ministry of Defence said no further Royal Air Force aircraft were due to depart Kabul on Monday. Another 150 British nationals were due to arrive in the UK from Kabul on Tuesday morning.
The Foreign Office has advised more than 4,000 British citizens thought to be in Afghanistan to leave.
On Thursday night, the government announced about 600 UK troops would be sent to the country to help British and eligible Afghan nationals leave.
The MoD said further personnel would be forward deployed to the region and able to move to Afghanistan if needed, while more troops would be held at readiness in the UK.
The Pentagon said the US would send another battalion to help, bringing the total US forces on the ground to about 6,000.
'Lesson to learn'
Speaking to broadcasters following a meeting of the government's emergency Cobra group on Monday, Mr Raab said there had been "surprise" at the speed of the Taliban's progress.
He said: "Everyone, I think, has been surprised by the scale and the pace at which the Taliban have taken over in Afghanistan, and that's a lesson that we've all got to learn from.
"But the truth is what matters right now is focusing on getting British nationals out, getting out those who have so loyally served the UK, and making sure that the gains that we've made over 20 years are not lost."
Asked about the number of refugees the UK might be willing to take, Mr Raab said he was unable to commit to taking in a specific number, but that the government was considering the next steps.
"We're obviously a big-hearted nation, we've got the criteria for asylum that is set in law – we work with the UN on that.
"We're working very carefully at what kind of further commitment we might make".
Officials are looking at a potential response similar to the resettlement of people from Syria in 2014 – which saw the UK accept refugees in greatest need, including survivors of violence, and women and children.
Mr Raab said the UK would work with its international partners to hold the Taliban to account over the group's commitments, including a pledge to prevent Afghanistan becoming a base for terrorism.
Downing Street said the British ambassador to Afghanistan, Sir Laurie Bristow, was working from the airport in Kabul, alongside UK staff and the armed forces, to process visas for eligible Afghans.
image sourceGetty Imagesimage captionSir Laurie Bristow was appointed British ambassador to Afghanistan in June
There have been warnings that Afghan interpreters who helped British forces could be "left behind" after Defence Secretary Ben Wallace said "some people won't get back".
Former Grenadier Guard Julian Perreira told BBC Radio 4's PM programme he was trying to reassure some interpreters, but added: "I just haven't got the heart to tell them that I think their worst fears may be coming true – that they may be left behind."
Most Afghan nationals eligible for relocation to the UK are those who have worked for the British government in frontline roles "that made a material difference to the delivery of the UK mission" in the country.
This group includes interpreters as well as cultural advisers and embassy staff. Others eligible are those deemed to be at high and imminent risk, according to the MoD.