Five dead, Americans and civilian casualties, after twin blasts at Kabul airport

Two explosions struck near the main gate of Kabul airport Thursday, causing multiple casualties in what the US military labelled a "complex attack" that took place as countries raced to complete evacuations from Afghanistan.

Pentagon spokesman John Kirby said there were "a number" of US and civilian casualties in the bombings, which came just hours after western officials said they had intelligence that suicide bombings were planned against the airport.

"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," Kirby said in a tweeted statement.

"We can also confirm at least one other explosion at or near the Baron Hotel, a short distance from Abbey Gate," he said.

The Baron Hotel, about 200 yards (meters) from the Abbey Gate, had been used by some western nations as a staging point for evacuations since the airlift began on August 14.

The US State Department said there were also reports of gunfire.

"US citizens should avoid traveling to the airport and avoid airport gates. Those at the Abbey Gate, East Gate, or North Gate now should leave immediately," it said.

Thousands of people have massed over the past 12 days near the Abbey Gate and other entrances to the Hamid Karzai International Airport, hoping to be evacuated after the Taliban took control of the country.

US officials say the Taliban has cooperated with the evacuation efforts.

But US and allied officials said in the past day that they had intelligence that suicide bombers tied to the Afghan arm of the Islamic State group -- the Islamic State-Khorasan (IS-K) -- were threatening to attack the airport ahead of Washington's August 31 deadline to finalize the evacuation.

The group is known to be at odds with the Taliban.

Earlier Thursday, Britain's armed forces minister James Heappey called the threat "imminent." 

Britain's Ministry of Defense said after the explosion that they were "working urgently" to understand what happened and how that would impact evacuation operations.

"Our primary concern remains the safety of our personnel, British citizens and the citizens of Afghanistan. We are in close contact with our US and other NATO allies at an operational level on the immediate response to this incident," the ministry said.

Most member nations of the US-led coalition said Thursday they had wound up or would soon end their own evacuation flights from Hamid Karzai International Airport.

The total number of people who have been taken out of the US-controlled hub since the international airlift began on August 14 hit 95,700 Thursday, including both Afghans and foreign nationals.

President Joe Biden said Tuesday that the United States would stick to its deadline of withdrawing all troops from Afghanistan by August 31, to end the two-decade US-led war there.

A spokesman for the Taliban, which seized Kabul on August 15 to cap a lightning campaign against government forces, said Tuesday the evacuation operation had to end on August 31.