A senior Taliban source said the group 'welcomed' the strike, in an indication of awkward cooperation with the US

By Roland Oliphant ; Jamie Johnson and Suddaf Chaudry | Telegraph

A US drone strike killed several Islamic State suicide bombers on their way to carry out a second attack on Kabul airport, in an apparent sign of uneasy security cooperation with the Taliban.

The strike hit a vehicle packed with explosives in a residential area of Kabul on Sunday, triggering a blast that could be heard across the city, US and Taliban officials said.

Nine civilians from one family, including six children, were killed in the strike, a witness told CNN.

A spokesman for US Central Command said late on Sunday it was investigating whether civilians were killed in the airstrike.

A senior Taliban source told the Telegraph that the group "welcomed" the strike, in an indication of a reluctant alignment with the Biden administration over the threat posed by the Islamic State offshoot in Afghanistan known as IS-K.

This was followed by the sound of rockets flying across Kabul on Monday morning, according to AFP journalists in the city.

People living near the airport said they heard the sounds of the missile defensive system being activated. Smoke could be seen rising near the airport.

Colonel Richard Kemp, former commander of British troops in Afghanistan, said the UK faced "the greatest danger from terrorism since Islamic State at its height".

In a significant concession to international pressure, the Taliban walked back a threat to close the borders after the US withdrawal.

Ninety countries including the United States and Britain said in a joint statement on Sunday that they had received assurances from the Taliban promising safe passage for Afghans who wished to leave the country after the airlift ends.

Mr Biden has ordered all American forces to leave Afghanistan by Tuesday, ending America’s longest war after nearly 20 years.

The last civilian evacuation flights were expected to leave by Sunday evening. A US military source said most troops would likely be withdrawn on Monday, leaving only a skeleton presence of US marines.

But a senior aide to US President Joe Biden said America planned to continue targeting members of IS-K after the August 31 withdrawal deadline for US troops.

President Joe Biden “will stop at nothing to make IS-K pay,” said Jake Sullivan, the US national security adviser.

On Sunday, Mr Biden and First Lady Jill Biden attended a ceremony for the American military victims at Dover Airport base in Delaware to receive the remains of 13 US servicemen killed in an IS-K suicide attack on crowds at Kabul airport's Abbey Gate last week. At least 169 Afghans were also killed in the blast.

American military officials said "several" would-be suicide attackers were killed in the strike in Kabul on Sunday afternoon.

US Navy Captain Bill Urban, a military spokesman, said the strike was carried out in "self-defence".

"We are confident we successfully hit the target," Captain Urban said. "Significant secondary explosions from the vehicle indicated the presence of a substantial amount of explosive material."

The Taliban confirmed the strike and said the attackers were on their way to Kabul airport when they were hit.

Initial reports said civilians including a child had been killed. The US said it was investigating.

A Taliban spokesman told CNN that the group condemned the attack as a violation of Afghanistan's sovereignty.

It was the second US strike against IS-K since the suicide attack outside Kabul airport's Abbey Gate on Thursday. The Pentagon said it killed two of the attack's IS-K planners in a separate drone strike on Saturday.

Generals given the 'green light'

Mr Biden, who said in a statement that the strike "would not be the last," was reported to have given generals the “green light” to strike the group without seeking White House approval.

The president’s “guidance is to just do it,” a source told Politico. “If we find more, we will strike them.”

That campaign is likely to see increasing convergence with the new Taliban government, despite deeply ingrained suspicions on either side.

Bilal Kareemi, a Taliban spokesperson, told CNN it was "not right to conduct operations on others' soil."

But a Taliban source told the Telegraph that IS-K was a “real concern” and that the strike was to be “welcomed".

The source said that he believed the terror group had increased the number of safe houses in the capital from which it is recruiting and that the Taliban wanted to root it out with “significant force.”

He added that the group was alerted to the scale of the IS-K threat after receiving intelligence about a planned attack on Kabul's Shia community, which was then prevented.

IS-K is the Islamic State splinter group that emerged in 2014. Although both are hard-line Sunni Islamist movements, it is a bitter foe of the Taliban and the two have fought pitched battles for control of territory.

After Thursday's attack on the airport, General Kenneth McKenzie, the head of US Central Command, said the US had shared enough intelligence with the Taliban to help them “act in time and space to try to prevent these attacks."

He said such cooperation had probably thwarted other attacks.

Some analysts have warned that there is overlap between members of the Taliban, IS-K and the Haqqani-network, a family led militant group from the Pakistani border area that is aligned with the Taliban leadership but maintains a large degree of autonomy.

Questions also remain about how Thursday’s attackers managed to get through the Taliban checkpoints on the roads approaching the airport.

Anthony Blinken, the US Secretary of State, said that there is “unlikely” to be a US diplomatic presence in Afghanistan come Wednesday, but said the effort to help people leave the country would continue.

“There's no deadline on that effort. And we have ways, we have mechanisms to help facilitate the ongoing departure of people from Afghanistan if they choose to leave,” he said.

Mr Sullivan said there was still time for the roughly 300 American citizens still awaiting evacuation to make it to the airport and be put on flights.

A Western official told Reuters that around 1,000 civilians were at the airport awaiting flights on Sunday morning.

The remarks came as Taliban's supreme leader, who has never been seen in public, has returned to Afghanistan to assume control of the new government.

Hibatullah Akhundzada, who is widely expected to assume the role of a supreme leader while a council of other Taliban leaders handles day-to-day government, is in Kandahar and will make a public appearance soon, a spokesman said.

Foreign Secretary Dominic Raab will call for "pragmatic" engagement with the Taliban to make sure they stand by their promises of safe passage at a meeting of foreign ministers of the G7, Nato and Qatar on Monday.

Britain, the US and France will also put forward a draft resolution calling on the Taliban to respect freedom of movement, prevent Afghanistan from being used as a base for terrorist attacks and ensure humanitarian access for UN agencies at a meeting of the UN Security Council.