Last-ditch evacuation flights took off from Kabul airport on Friday, a day after twin suicide bombings on crowds trying to flee Taliban-controlled Afghanistan killed at least 85 people, including 13 US servicemen.
The bombings, claimed by the Islamic State jihadist group, injected further panic into the final days of an already frenzied US-led airlift.
The attacks targeted US forces, but hit hardest the mass of people fearing life under the Taliban who converged on the airport in a desperate bid to board a flight out.
At least 72 people among the crowd were killed, as well as the 13 American troops, according to various authorities.
But with people searching for missing relatives in hospitals on Friday, there were fears the death toll would climb.
President Joe Biden, under enormous pressure over his administration's handling of the Afghan crisis, vowed to punish those responsible.
"We will not forgive. We will not forget. We will hunt you down and make you pay," he said.
However Biden, determined to end two decades of war in Afghanistan and citing fears of more IS attacks, also insisted that he would stick to his August 31 deadline to end the airlift.
On Friday morning, some evacuation flights resumed with queues of people seen lining up on the tarmac but there were no more crowds near the sites of the blasts, according to AFP reporters.
Britain and Spain announced their evacuation operations would end Friday, after Canada and Australia had already stopped their flights.
More than 100,000 people have been flown out of the country since the Taliban swept into power on August 15.
- 'More extreme' -
The Taliban have promised a softer brand of rule compared with their first stint in power, which ended in 2001 when the United States invaded because they gave sanctuary to Al-Qaeda.
But many Afghans fear a repeat of the their brutal interpretation of Islamic law, as well as violent retribution for working with foreign militaries, Western missions or the previous US-backed government.
Western allies have repeatedly warned the United States that it is impossible to get all at-risk Afghans out by Tuesday.
The Taliban have allowed US-led forces to conduct the airlift, while planning to finalise their own government as soon as the American troops left.
But the IS jihadists, bloody rivals of the Taliban with their own track record of barbaric attacks, were intent on capitalising on the chaos in Kabul.
In recent years, the Islamic State's Afghanistan-Pakistan chapter has been responsible for some of the deadliest attacks in those countries.
It has massacred civilians at mosques, shrines, public squares and even hospitals.
"These are people that are even more extreme than the Taliban and are basically at war with the Taliban. So it is a horribly complex situation," Australian Defence Minister Peter Dutton said.
- Terror, devastation -
The attackers targeted people trying to reach access gates at the airport, creating scenes of terror and devastation.
Immediately after the blast, one man held a semi-conscious victim by the elbow, trying to stop his head from slipping beneath the surface of the murky water in a canal along the perimeter of the airport.
"I will never, ever want to go (to the airport) again. Death to America, its evacuation and visas," said Milad, who was near the first blast with his wife and three children, told AFP.
The Italian NGO Emergency said the hospital it operates in Kabul had been overwhelmed by more than 60 casualties, 16 of whom were pronounced dead on arrival.
The injured "could not speak, many were terrified, their eyes totally lost in emptiness, their gaze blank", the hospital's medical coordinator Alberto Zanin said in a post on the group's Twitter account.
- 'Bear responsibility' -
The attacks led to the worst single-day death toll for the US military in Afghanistan since 2011.
A clearly shaken Biden went before TV cameras to address the American people, describing the killed US troops as heroes.
Asked by a reporter if he bore any responsibility for the deaths, Biden said: "I bear responsibility fundamentally for all that's happened of late."
The Taliban, which condemned the blasts, emphasised they happened in an area under US military control.
The attacks were also denounced around the world, with Britain describing them as barbaric and Germany as heinous.
The United Nations called an urgent meeting of the permanent members of the Security Council for Monday.