The US Defence Department said Thursday that the number of American troops killed in the suicide bombings at Kabul airport rose by one to 13, and the number of wounded was 18.
"A thirteenth US service member has died from his wounds suffered as a result of the attack on Abbey Gate," Central Command spokesman Captain Bill Urban said in a statement.
Ten of those killed and several wounded were US Marines, Marine Corps spokesman Major Jim Stenger said in a statement. "We mourn the loss of these Marines and pray for their families," Stenger said.
"Our Marines will continue the mission, carrying on our Corps' legacy of always standing ready to meet the challenges of every extraordinary task our Nation requires," he said.
The military has yet to provide any details of what occurred in the attack, which was carried out by the Afghanistan branch of the Islamic State jihadist group.
The outer perimeter of access to the airport is controlled by the Taliban, and the airport gates are managed under heavy security by the Marines and other troops.
They have been in charge of allowing passage of into the airport of thousands of people each day seeking to flee the country after the Taliban seized control of the government.
That requires them to examine the evacuees for their travel papers and security risks, General Kenneth McKenzie, the commander of the US Central Command, said Thursday.
"We have to check people before they get onto the airfield," McKenzie said. "We can't do that with standoff. You ultimately have to get very close to that person," he said.
Islamic State bombers kill dozens at Kabul airport
Islamic State suicide bombers attacked crowds of people gathered outside Kabul airport hoping to flee Taliban-controlled Afghanistan, killing dozens including 13 US troops, as President Joe Biden vowed to hunt down those responsible.
The Taliban said the two blasts killed between 13 and 20 people. A health official in the previous government said the toll could rise to 60.
The Islamic State group claimed responsibility for the attack, which added more urgency and heartbreak to the frantic US-led campaign to airlift people out of Afghanistan now that the hardline Islamist group has seized power.
The airport blasts came as the August 31 deadline looms for the United States to withdraw its troops, and for it and other Western countries to end a massive airlift that has already evacuated nearly 100,000 people.
With the crisis in Afghanistan rocking his presidency to the core, a clearly shaken Biden went before TV cameras to address the American people after the worst single-day death toll for the US military in Afghanistan since 2011.
He said the US soldiers who died in the airport blasts were heroes, and vowed to catch those behind the attack. "We will not forgive. We will not forget. We will hunt you down and make you pay," he said.
Biden said the evacuation effort would proceed and end on schedule at the end of the month.
Asked by a reporter if he bore any responsibility for the death of the US service members killed Thursday, Biden said: "I bear responsibility fundamentally for all that's happened of late."
The attack marked a deadly escalation of the drama unfolding at the airport. It is the only part of the country under foreign control following the Taliban's return to power on August 15, and huge crowds have massed in the hope of being evacuated.
Taliban spokesman Zabihullah Mujahid told AFP that between 13 and 20 people were killed and 52 wounded in the twin blasts, while Kabul hospitals reported six dead and up to 90 wounded.
A health official in the pre-Taliban administration said the death toll could rise to 60, but added that he could not be named and other sources could not confirm the figure.
General Kenneth McKenzie, head of the US Central Command, initially said 12 US troops were killed. But another soldier died later, and the latest US injury toll is 18, the Central Command said.
McKenzie said an unspecified number of Afghan civilians were killed.
McKenzie said the blasts have been assessed as coming from Islamic State suicide bombers, and that the US airlift would continue despite the attack.
"ISIS will not deter us from accomplishing the mission," he said.
The United States expects more Islamic State attacks in Kabul and is prepared to retaliate, McKenzie told a news conference.
Later, in the early hours of Friday, a huge blast was heard in Kabul. Mujahid said this was a controlled explosion by US troops destroying equipment at the airport, a statement that has yet to be independently confirmed.
Biden had earlier cited an "acute" terrorist threat from the regional chapter of the jihadist group.
The Taliban, a rival of the Islamic State, condemned the blasts, and said they happened in an area under US military control.
- 'Total panic' -
Graphic video shared on social media showed bodies lying semi-submerged in a canal adjacent to the airport, where thousands have gathered since the Taliban takeover of August 15 hoping for a flight out.
"When people heard the (first) explosion there was total panic," a man name Milad told AFP.
"The Taliban then started firing in the air to disperse the crowd. I saw a man rushing with an injured baby in his hands."
The US government and its allies had raised the alarm earlier in the day with a series of advisories warning their citizens to avoid the airport.
After the blasts, images posted on social media showed men ferrying wounded people to safety in wheelbarrows.
In another picture, a boy was seen clutching the arm of a man whose clothes were soaked in blood.
- 'Truly heartbreaking' -
More than 95,000 Afghans and foreigners have fled Afghanistan via the US-led airlift since the hardline Taliban movement took control of the country.
Biden has not budged on the August 31 deadline -- even as some foreign nations warned they would be forced to leave at-risk Afghans behind.
Several Western allies have already wrapped up their airlift operations including Canada, whose government said it was "truly heartbreaking" to leave behind those who wanted to be rescued.
The airport attack on unarmed people desperate to flee to safety drew condemnation from around the world, with Britain describing it as barbaric and Germany as heinous. The United Nations called an urgent meeting of the permanent members of the Security Council for Monday.
In Washington, Republicans said Congress should end its summer vacation and reconvene to discuss what they called the chaotic US withdrawal from Afghanistan.
- Islamic State threat -
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.
The group has especially targeted Muslims from sects it considers heretical, including Shiites.
But while IS and the Taliban are both hardline Sunni Islamist militants, they are rivals and oppose each other.
The Taliban have promised a softer brand of rule from 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 Taliban's brutal interpretation of Islamic law, as well as violent retribution for working with foreign militaries, Western missions or the previous US-backed government.
There are particular concerns for women, who were largely banned from education and employment and could only leave the house with a male chaperone during the group's 1996-2001 rule.
Over 100,000 evacuated: White House
More than 100,000 people from Afghanistan have been evacuated since August 14, the eve of the Taliban's return to power, the White House said Thursday.
"Since August 14, the US has evacuated and facilitated the evacuation of approximately 100,100 people," the White House said in a statement issued hours after Islamic State suicide bombers killed dozens, including 13 US troops, as they attacked crowds gathered outside Kabul airport hoping to flee.
The announcement came as the August 31 deadline looms for the United States to withdraw its troops, and for it and other Western countries to end their massive airlift.
"A total of approximately 7,500 people were evacuated from Kabul," over a 12-hour period on Thursday, the White House said.
This, it added, was the result of 14 US military flights which carried approximately 5,100 evacuees and 39 coalition flights which carried 2,400 people.
On Thursday, US President Joe Biden said the evacuation effort would proceed and end on schedule at the end of the month.
Australian troops out ahead of blasts
Australia said Friday it pulled all its troops out of Afghanistan on the eve of the Kabul airport bombings after receiving "very clear intelligence" of an impending attack.
Australian Defence Minister Peter Dutton said the Australian authorities had sent warnings in text messages on Thursday to Australian citizens and those in the area of the attack. "There was very clear intelligence that ISKP intended to strike and strike hard, and they have done that,” he told Nine Network television, referring to an Islamic State-affiliated group active in parts of south and central Asia.
"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," Dutton said.
"I am very pleased and relieved that our soldiers have departed from Kabul and we took the decision to lift the last of our people yesterday and they are safely in the United Arab Emirates."
Australia deployed 39,000 troops over two decades as part of US and NATO-led operations in Afghanistan.
Dutton said Australian Defence Force troops had now halted evacuations because of the dangers on the ground. "In that situation we cannot continue to put our ADF personnel and their lives at risk. And that is the situation, the reality of what is on the ground at the moment, which has not made it possible for us to lift more people out," he said.
The Australian defence minister warned of further attacks. "As we have seen overnight and as the intelligence continues to indicate, more terrorist attacks are likely. People should avoid gatherings. They should avoid public places. And they should be very careful of their own safety and security in what is a war-like condition."
Dutton said he grieved over the loss of life, in particular US troops who had helped Australian citizens and visa holders to reach the Kabul airport for evacuation. "Everyone is devastated by this," he said.