Approximately 1,500 people who may be Americans are left in Afghanistan, Blinken says

Blinken said the US has "evacuated at least 4,500 American citizens and likely more" since August 14, and more than 500 were evacuated in the last day alone. "Over the past 24 hours we've been in direct contact with approximately 500 additional Americans and provided specific instructions on how to get to the airport safely," he said speaking at the State Department.

"For the remaining roughly 1,000 contacts that we had who may be Americans seeking to leave Afghanistan, we're aggressively reaching out to them multiple times a day through multiple channels of communication," Blinken added.

But while the pace of US evacuations from Afghanistan has picked up considerably in recent days, Biden administration officials have repeatedly voiced concern about security around Hamid Karzai International Airport in Kabul. The US believes ISIS-K, which is a sworn enemy of the Taliban, wants to create mayhem at the airport and has intelligence streams suggesting it is capable and planning to carry out multiple attacks, a US defense official told CNN.

Blinken said Wednesday that "it's hard to overstate the complexity and the danger of this effort," citing Taliban control and the "very real possibility of an ISIS-K attack."

"We're operating in a hostile environment in a city and country now controlled by the Taliban with the very real possibility of an ISIS-K attack. We're taking every precaution but this is very high-risk. As the President said yesterday, we're on track to complete our mission by August 31 provided the Taliban continue to cooperate and there is no disruption to this effort," he said.

"There is no deadline on our work to help any remaining American citizens who decide they want to leave to do so, along with the many Afghans who have stood by us over these many years and want to leave and have been unable to do so. That effort will continue every day past August 31," he said.

On Tuesday, as he confirmed his decision not to extend the evacuation deadline beyond August 31, President Joe Biden acknowledged the growing threat that the group poses to the airport.

"Every day we're on the ground is another day we know that ISIS-K is seeking to target the airport and attack both US and allied forces and innocent civilians," the President said.

As a result, the Biden administration is in touch with US allies about securing the Kabul airport and efforts to keep it up and running, a senior State Department official said Wednesday. It is unclear if there will be any agreement to keep the airport open by the time the US military leaves.

Blinken noted Wednesday that some may have left the country, some may not actually be Americans and some may choose to stay. He said the State Department believes "the number of Americans actively seeking to leave Afghanistan is lower, likely significantly lower," but noted that they are "dynamic" calculations.

Americans are not required to register with the State Department, Blinken said, making precise counts difficult.

But even as the United States flies tens of thousands of people out of the country, many Afghans who assisted the war effort are still awaiting their turn to leave. The dangerous and chaotic scenes outside the airport have made it virtually impossible for Afghans -- even those with green cards, specific instructions from the US embassy, or ailing children -- to make it onto the airport grounds.

This story is breaking and will be updated.

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