LONDON: British troops have left Kabul, ending the UK's evacuation operation and its 20-year military involvement in Afghanistan.
Prime Minister Boris Johnson praised the "heroic" evacuation effort, even as the government acknowledged some eligible Afghan civilians had been left behind.
The UK's top military officer conceded that "we haven't been able to bring everybody out."
The UK government said late Saturday that about 1,000 troops who ran an airlift of British nationals and Afghan civilians had departed from Kabul airport, hours after the final evacuation flight for civilians.
Most countries apart from the United States had already left.
Before departing, Britain's ambassador to Afghanistan, Laurie Bristow, said from Kabul airport that it was "time to close this phase of the operation now."
"But we haven't forgotten the people who still need to leave," Bristow said in a video posted on Twitter.
"We'll continue to do everything we can to help them. Nor have we forgotten the brave, decent people of Afghanistan. They deserve to live in peace and security."
Britain says it has evacuated more than 15,000 people from Kabul in the past two weeks but that as many as 1,100 Afghans who were entitled to come to the UK have been left behind.
Some British lawmakers who have been trying to help stranded constituents and their families believe the true total is higher.
"We haven't been able to bring everybody out, and that has been heartbreaking, and there have been some very challenging judgments that have had to be made on the ground," the head of British armed forces, Gen. Nick Carter, told the BBC.
Foreign citizens from around the world and the Afghans who worked with them have sought to leave the country since the Taliban's swift takeover this month after most US forces departed.
About 117,000 people have been evacuated through Kabul airport, according to American officials.
Meanwhile, the US State Department is urging all Americans in the vicinity of the Afghanistan's Kabul airport to leave the area immediately because of a specific, credible threat.
The warning early Sunday morning says US citizens should avoid traveling to the airport and avoid all airport gates at this time.
It specifically noted the South (Airport Circle) gate, the new Ministry of the Interior, and the gate near the Panjshir Petrol station on the northwest side of the airport.
A suicide bombing at the airport on Thursday killed at least 169 Afghans and 13 US service members.
Taliban forces sealed off Kabul's airport Saturday to most Afghans hoping for evacuation and most NATO nations flew out their troops after two decades in Afghanistan, winding down a frantic airlift that Western leaders acknowledged was still leaving many of their citizens and local allies behind.
The United States, which says round-the-clock multinational flights have evacuated 117,000 people since the Taliban claimed Kabul on Aug.15, was keeping up airlifts ahead of President Joe Biden's Tuesday deadline for withdrawal.
Britain also was carrying out its final evacuation flights Saturday, though Prime Minister Boris Johnson promised to "shift heaven and earth" to get more of those at risk from the Taliban to Britain by other means.
Britain's ambassador to Afghanistan, Laurie Bristow, said in a video from Kabul airport and posted on Twitter that it was "time to close this phase of the operation now."
"But we haven't forgotten the people who still need to leave," he said.
"We'll continue to do everything we can to help them. Nor have we forgotten the brave, decent people of Afghanistan. They deserve to live in peace and security."
As the flow of planes leaving Kabul slowed, others arrived in cities around the world.
Afghans who managed to secure places on the last evacuation flights were heading for the Washington area and Philadelphia, Madrid, Birmingham, England, and elsewhere.
Some were relieved and looking forward to starting their new lives far from the Taliban, but others were bitter about having to flee.
In Spain, evacuee Shabeer Ahmadi, a 29-year-old journalist targeted by the Taliban, said the United States had doomed the work he and others had put into making Afghanistan a better place by allowing the insurgent group to reclaim power.
"They abandoned the new generation of Afghanistan," Ahmadi said.
An evacuation flight to Britain landed with an extra passenger on Saturday after the cabin crew delivered a baby girl mid-air, Turkish media reported.
The parents named her Havva, or Eve, and she was at least the fourth baby known to have been born to Afghan mothers who went into labor on evacuation flights.
Meanwhile, families of Afghans killed in Thursday's suicide bombing at the airport by an Islamic State group affiliate set about burying their dead, at least 169 Afghans and 13 U.S. service members died in the attack.
Among those killed was Belal Azfali, a 36-year-old contractor for a U.S.-funded project who had gone to the airport on his own, without his wife.
His remains were so disfigured that he could only be identified when someone picked up the family's repeated calls to the cellphone he had with him, relatives said.
The U.S. on Saturday released the identities of the 13 Marines, Navy and Army forces killed in the bombing.
They included at least one of the Marines, recently promoted Marine Sgt. Nicole Gee, 23, who were seen in widely circulated photos cuddling Afghan infants they had temporarily rescued from the crush of the crowds outside the airport gates earlier this month.
Taliban spokesman Zabihullah Mujahid claimed Saturday that the group's forces were holding some positions within the airport and were ready to peacefully take control of it as American forces flew out.
But Pentagon spokesman John Kirby denied the claim.
The Taliban did deploy extra forces outside of the airport to prevent large crowds from gathering in the wake of Thursday's bombing .
New layers of checkpoints sprang up on roads leading to the airport, some manned by uniformed Taliban fighters with Humvees and night-vision goggles captured from Afghan security forces.
Areas where the crowds had gathered over the past two weeks in the hopes of fleeing the country were largely empty.
Officials said U.S. forces were taking every precaution they could at the airport, as there were concerns that IS, which is far more radical than the Taliban, could strike again.
Maj. Gen. Hank Taylor said during a Pentagon news conference Saturday that a retaliatory drone strike Biden ordered had killed two "high-profile" IS militants believed to have been involved in planning or facilitating attacks, not one, as initially reported.
"The fact that two of these individuals are no longer walking on the face of the earth, that's a good thing," Pentagon spokesman John Kirby said.
An Afghan who worked as a translator for the U.S. military said he was with a group of people with permission to leave who tried to reach the airport late Friday.
After passing through three checkpoints they were stopped at a fourth.
An argument ensued, and the Taliban said they had been told by the Americans to only let U.S. passport-holders through.
"I am so hopeless for my future," the man told The Associated Press after returning to Kabul, speaking on condition of anonymity because of security concerns.
"If the evacuation is over, what will happen to us?" Kirby, the Pentagon spokesman, said Saturday that Afghans who had worked with American forces still were being allowed in.
According to a State Department spokesperson, 5,400 Americans and likely more have been safely evacuated from Afghanistan since Aug.14, including nearly 300 Americans in the last day.
Another 350 Americans were still seeking to leave the country, and those were the only ones the department could confirm were still in Afghanistan.
The US has evacuated and facilitated the shifting of approximately 111,900 people from the Hamid Karzai International Airport in Kabul since August 14, the White House has said.
The US evacuated approximately 6,800 people in the time period between August 27 at 3:00 AM EDT and August 28 at 3:00 AM EDT, following the deadly suicide attack near the Kabul airport on Thursday, it said.
This is the result of 32 US military flights (27 C-17s and 5 C-130s) which carried approximately 4,000 evacuees, and 34 coalition flights which carried 2,800 people, according to a White House official.
Since August 14, the US has evacuated and facilitated the evacuation of approximately 111,900 people.
Since the end of July, we have re-located approximately 117,500 people, the official said.
Meanwhile, Senator Roger Marshall led Representatives Jimmy Panetta and Mike Gallagher in sending a bipartisan, bicameral letter to President Joe Biden, urging him to safely evacuate American citizens, Afghan Special Immigrant Visa (SIV) applicants and other at-risk populations, including women and children, from Afghanistan.
"We urge you to provide transparency regarding how the administration will safeguard the approximately 1,500 American citizens still remaining in Taliban-controlled Afghanistan, SIV applicants, and other at-risk populations," they said.
The lawmakers said the US military should commit to responding with overwhelming force to continued attacks on or around the Kabul airport, any attack on American citizens attempting to evacuate or any attempt to hold them hostage.
"The administration must keep its commitment to our Afghan allies who risked their lives supporting the US or NATO campaigns by evacuating remaining SIV applicants," they said.
The lawmakers said the Biden administration must ensure that the US military is prepared and committed to holding Hamid Karzai International Airport until the evacuation mission is complete.
In a separate letter, Senator Michael Bennet, a member of the US Senate Select Committee on Intelligence, joined 28 other lawmakers in urging the Biden administration to expedite efforts to evacuate Afghans at risk as the situation in Afghanistan deteriorates.
In their letter to Secretary of State Antony Blinken and Secretary of Homeland Security Alejandro Mayorkas, they specifically pushed for the administration to explore the use of parole to speed up entry for Afghans with already approved visa petitions.
"As the situation on the ground in Afghanistan becomes more dangerous, thousands of Afghans are desperately seeking to leave the country to avoid possible persecution."
"We fully support efforts to provide humanitarian protection to those Afghan nationals in need. However, we write to draw your attention to the possibility that there are many nationals from Afghanistan in the family and employment-based immigration system for whom a visa is not yet available due to visa caps in immigration law," wrote Bennet and his colleagues.
France is holding discussions with the Taliban and Qatar with a view to retrieving Afghans on France's list for evacuation who could not get out before France shut down operations at Kabul airport the night before.
French President Emmanuel Macron said the talks Saturday "remain fragile and very provisional."
He spoke at a news conference in Baghdad during the first leg of a two-day visit to Iraq.
The emir of Qatar was among leaders present at a regional summit centered on Iraq co-organized by France.
"Our goal is that in the days, weeks months ahead (France could) proceed with targeted evacuation operations of these men and women whom we identified," Macron said, suggesting that airlines could be used "with security conditions that remain to be defined."
He did not further elaborate.
Such operations would necessarily take place in a "different framework" from the mass evacuations headed by the United States, which is set to pull out of Kabul on Tuesday.
France made its last flight out Friday.
The operations France envisages would be "systematically negotiated with the Taliban," in particular the security aspect.
Macron also set out three "essential prerequisites" for discussing any future political relations with the Taliban, including that they "absolutely respect" humanitarian rights and the right of Afghans who want to leave to seek protection be able to do so, notably artists, intellectuals, journalists and women.
He said the Taliban must also respect a "red line" regarding all terrorist groups and respect human rights, in particular the dignity of women.
The French ambassador to Kabul, evacuated Friday, is to continue working in Paris in that function.
Since mid-August, France evacuated about 2,830 people, the great majority of them Afghans on some 15 flights after pulling out 630 personnel and their families in the spring.
France, which withdrew its troops from Afghanistan at the end of 2014, had also previously taken in 830 people working for the French army.