Two explosions occurred outside Kabul airport, officials said, amid the evacuation of thousands of people from Western countries.
British defense sources said that one of the explosions occurred in a hotel where British soldiers and journalists were staying, followed by small arms fire, while the second explosion occurred in Abbey Gate.
The Pentagon press secretary said the attack resulted in “a number of American and civilian casualties” but the exact number remains unclear.
Taliban officials said at least 13 people were killed, including children.
The Associated Press quoted eyewitnesses as saying they had seen several people apparently killed or injured.
The White House said President Joe Biden was briefed on the blast.
A spokesperson for No. 10 confirmed that Prime Minister Boris Johnson had been briefed on the situation at the airport in Kabul and said he would chair the Cobra meeting later in the afternoon.
Stewart Ramsay, chief correspondent for Sky News, said that his sources told him that the explosion was caused by a suicide bomber who blew himself up in one of the channels.
He added: “We are not sure of the number of casualties, we must assume a number of civilians, but the initial reports suggest that US soldiers were injured, not British soldiers, but American soldiers.”
“It was very clear that it was a very dangerous place because of the numbers of people going through, and the fact that there were no real checks on what people were carrying or wearing to get into this canal area.”
Ramsay said the attack was “not inside the airport itself, but on the wall around the airport, a road that leads to the processing area that the British initially set up”.
The blast followed warnings earlier in the day that a “very deadly” terrorist attack at the airport could take place within hours.
Following the explosion near Kabul airport, the Defense Ministry tweeted: “We are working urgently to determine what happened in Kabul and its impact on the ongoing evacuation efforts.
“Our primary concern remains the safety of our personnel, British nationals and the citizens of Afghanistan. We are in close contact with the United States and our other NATO allies at the operational level regarding the immediate response to this incident.”
Deborah Haynes, Sky News’ foreign affairs editor, said she had previously spoken to an Afghan interpreter who was waiting outside Kabul airport with his three-month-old daughter, three-year-old son and his wife.
He was waiting five days to be processed and had all the correct documents.
Since the explosion, Haynes has been unable to contact him.
She says he told her he was willing to risk his life and that of his family in their desperation to get out of Afghanistan.
Welden’s party MP Nusrat Ghani said on Twitter that she was on the phone with “an Afghan outside the airport when he heard the explosion”.
She added, “We pray to God that he departs safely and that his family come out of this nightmare safely.”
Shadow Secretary of State Lisa Nandy described the incident as a “horrific and cowardly attack on those already fleeing unimaginable horrors”.
Devastating reports from Kabul. This is a horrific and cowardly attack on those who have already fled from unimaginable horrors.
My thoughts are with the Afghan people and the British, American and international staff who stayed behind to save as many lives as possible. https://t.co/9r8yJJTQOy
– Lisa Nandy (@lisanandy) August 26, 2021
“My thoughts are with the Afghan people and the British, American and international staff who stayed behind to save as many lives as possible,” she added.
The UK, US and other countries are moving to end evacuations of tens of thousands of citizens before the August 31 deadline.