The UK's evacuation programme in Afghanistan is "operating at full pace" but the changing political situation means it "can't afford to pause and wait", a military commander has said.
Vice Adm Sir Ben Key, who is running the evacuation, said around 300 people had been flown out so far.
In total, the UK hopes to help 6,000 to 7,000 British nationals and eligible Afghan staff to leave, he said.
But Sir Ben said the operation was dependant on the security situation.
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There were chaotic scenes at Kabul airport on Monday, as thousands tried to flee the country after the Taliban seized control of the capital.
A number of people died and large crowds on the runway led to all flights being halted for several hours.
However, Chief Joint Operations Vice Admiral Sir Ben said the situation was now "much calmer".
"I'm very confident that we now have a stable airfield in which we can get on with the business, alongside all of our allies and partners, that we need to do," he said.
He said three flights had landed in Kabul so far on Tuesday and more were planned.
Military aircraft are also flying from Afghanistan to airports across the region, where people can then be put on civilian charter flights, he added.
The UK has sent about 900 troops to Afghanistan to help evacuate British nationals and Afghans who are eligible to resettle in the UK.
This group includes Afghans who worked for the British government, as well as interpreters, cultural advisers and embassy staff. Others eligible are those deemed to be at high and imminent risk, according to the Ministry of Defence.
Sir Ben said the UK wanted to bring as many people back as quickly as possible.
"We will go for as long as it takes us to either meet the demand or when the security situation means that we're no longer operating with consent," he added.
However, he said it was up to eligible individuals to make their own way to the airport and the Taliban were now controlling access points.
So far, he said the Taliban had "seemed acquiescent and understanding of what we're trying to achieve" – but "we don't take it for granted".