U.S. officials are changing their evacuation strategy in Afghanistan after learning of potential threats from the Islamic State, the Associated Pressreported on Saturday.

A government official who spoke with the AP under the condition of anonymity said that small groups of Americans and others will be given instructions on how to meet members of the military for evacuation.

On Saturday, the U.S. embassy warnedof potential "security threats" outside the gates at the Kabul airport.

The embassy told citizens "to avoid traveling to the airport and to avoid airport gates at this time unless you receive individual instructions from a U.S. government representative to do so."

In a statement toNewsweek, a State Department spokesperson said officials issued the security alert "to avoid large crowds outside the airport gates – both for security purposes and as a means to make the processing as efficient as possible."

The spokesperson added that the State Department now has "the ability to communicate with Americans on a personalized basis."

"So, rather than offering blanket guidance that all Americans should consider traveling to the airport, we are in a position to offer tailored instructions – via email, over the phone, and over text, among other means," the spokesperson said.

This latest development comes as the U.S. government attempts to evacuates thousands of Americans and Afghan allies from Afghanistan after it fell to the Taliban last weekend.

President Joe Biden has said his deadline for completing his withdrawal of troops from Afghanistan is August 31. However, he told ABC News this week that the deadline could be extended if there are still Americans in the country at that point.

On Friday he vowed to evacuate all Americans from Afghanistan.

"Any American who wants to come home, we will get you home," Biden said.

He also said U.S. officials would do "everything that we can" to provide evacuation "for our Afghan allies, partners and Afghans who might be targeted because of their association with the United States."

It's unclear how many Americans are still in Afghanistan, though Biden told ABC News earlier this week that the number was between 10,000 and 15,000.

Pentagon officials speaking with reporters on Saturday said that large crowds at airport entrances posed security threats, including potential attacks from Al Qaeda and the Islamic State,The New York Times reported. However, Maj. Gen. William Taylor of the Pentagon's Joint Staff told reporters that military officials "have the ability to continue to process those who come to the gate" at the airport.

In the last 24 hours, three C-17 planes and 32 chartered jets left Kabul with nearly 4,000 people, the newspaper reported.

On Friday, Biden said there were 6,000 troops on the ground in Afghanistan "including the 82nd Airborne providing runway security, the Army 10th Mountain Division standing guard around the airport, and the 24th Marine Expeditionary Unit assisting the civilian departure."

"This is one of the largest, most difficult airlifts in history. And the only country in the world capable of projecting this much power on the far side of the world with this degree of precision is the United States of America," he added. (Credit: Newsweek)

•PHOTO: People wait to be evacuated from Afghanistan at the airport in Kabul on August 18, 2021 following the Taliban stunning takeover of the country. U.S. officials said Saturday that they had to change their evacuation strategy in Kabul after learning of potential threats from the Islamic State.AFP VIA GETTY IMAGES