"We can confirm an explosion outside Kabul airport. Casualties are unclear at this time. We will provide additional details when we can," he tweeted.
According to the Jerusalem Post, however, ten people have been killed and at least 15 people have been wounded, including some U.S. soldiers.
"President Joe Biden has been briefed on the explosion... he was in a meeting with security officials about the situation in Afghanistan when the explosion was first reported," Arab News said.
For several days now, Abbey Gate has been the main site through which thousands of people try to enter the airport seeking evacuation from Afghanistan. Crowds were also gathered around that entrance when the explosion occurred.
"US and allied officials have said they had intelligence that suicide bombers tied to the Afghan arm of Daesh - the so-called Islamic State-Khorasan (IS-K) - were threatening to attack the airport ahead of Washington's August 31 deadline to finalize the evacuation," the Arab News pointed out, adding that some Western countries had previously warned their citizens about a possible terrorist threat at the Kabul airport.
After the explosion, the U.K. Defense Ministry said it was working urgently to establish what has happened and its impact on the ongoing evacuation effort.
"Our primary concern remains the safety of our personnel, British citizens and the citizens of Afghanistan. We are in close contact with our U.S. and other NATO allies at an operational level on the immediate response to this incident,” it added.
A few minutes later the first explosion, the Pentagon confirmed another attack occurred outside a hotel where citizens of Western countries were staying.
"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," Kirby tweeted.