Two suspected suicide bombs have exploded outside Kabul airport
Full extent of death toll remains unknown
Pentagon confirms 12 US troops killed, and 15 more injured
Some reports say at least 60 Afghans have been killed
Terror group Isis-K claims responsibility for attack
Ministry of Defence say so far there have been no British casualties
Suicide bombers have struck the crowded gates of Kabul airport in a twin terror attack that has killed dozens of people including at least 12 Americans.
There is no complete death toll from at least two explosions, but video images uploaded by Afghan journalists showed dozens of bodies killed in tightly packed crowds outside the airport.
Isis-K, an affiliate of the so-called Islamic State in Afghanistan, has claimed responsibility for the attack.
The Pentagon has confirmed 12 US service members have been killed and 15 injured. The BBC has reported at least 60 deaths and 140 wounded, citing an Afghan health official.
A watery ditch by the airport fence was filled with bloodsoaked corpses, some being fished out and laid in heaps on the canal side while civilians searched for loved ones.
Several Western countries said the airlift of civilians was now effectively over, with the United States having sealed the gates of the airport leaving no way out for tens of thousands of Afghans who worked for the West through two decades of war.
Both explosions took place near the Abbey Gate entrance to the airport, where large numbers of refugees have gathered in recent days trying to flee the Taliban. The second explosion was accompanied by gunfire.
US Pentagon press secretary John Kirby added: "We also know that a number of Afghans fell victim to this heinous attack.
"Our thoughts and prayers go out to the loved ones and teammates of all those killed and injured.”
Prime Minister Boris Johnson said the UK will continue to work "flat out" evacuating as many as possible despite the “barbaric” terrorist attack at Kabul airport.
He said members of the US military “very sadly have lost their lives” in the attacks in Kabul, as well as “many Afghan casualties.”
He refused to comment on who may be behind the attack when speaking to journalists after chairing an emergency COBRA meeting.
Around 60 people wounded in the attack on Kabul airport on Thursday are being treated at a nearby surgical centre, according to Emergency, a charity that runs a network of war hospitals and first aid posts across Afghanistan.
The Ministry of Defence said: "There have been no reported UK military or UK Government casualties following the incidents in Kabul."
The Pentagon said: "We can confirm that the explosion at the Abbey Gate was the result of a complex attack that resulted in a number of US & civilian casualties. We can also confirm at least one other explosion at or near the Baron Hotel, a short distance from Abbey Gate. We will continue to update."
According to Afghan journalist Bilal Sarwary, an eyewitness told him that one of the explosions took place when a suicide bomber blew himself up in the middle of a large crowd near a sewage canal where Afghans had gathered to have their documents vetted.
Witnesses have described the chaos, with one former Royal Marine saying his vehicle was targeted by a gunman.
Paul Farthing, known as Pen, who founded the Nowzad shelter in Kabul, is aiming to get 200 dogs and cats out of the country alongside his animal shelter staff, said: “We’re fine but everything is chaos here.
“All of a sudden we heard gunshots and our vehicle was targeted, had our driver not turned around he would have been shot in the head by a man with an AK-47."
US officials cautioned their initial report attributing the cause to a suicide bomber may change.
Thousands of people have thronged around the airport in recent days as they try to board evacuation flights out of Afghanistan.
Conservative MP Alicia Kearns, a member of the foreign affairs and national security strategy committees, said there had been "so many hurt" in a bomb or gun attack at the Baron Hotel in Kabul.
She tweeted: "A bomb or attack with gun fire at northern gate of Baron’s hotel. Worried this will devastate evacuation – so many hurt. My heart is with all those injured and killed."
Tory MP Nus Ghani said she was on the phone to somebody outside Kabul airport when the explosion happened.
The Wealden MP tweeted: "Explosion at Kabul airport. I was on the phone to an Afghan outside the airport when he heard the explosion.
"Praying that he gets away safely and we get his family safe passage out of this nightmare."
Watch: Afghanistan: Boris Johnson says time remaining for Kabul evacuations is 'quite short' but 'overwhelming majority' of people have left