Two defense officials told NBC News that they are tracking specific threats from ISIS against the Kabul airport and those trying to get to the airport. With that, alternative ways are being developed to get people to the evacuation zone, the officials explained.

“We are executing an alternate path,” a defense official told NBC News. This includes gathering smaller groups of people at specific locations and then moving them to the airport in intervals. The goal is to get them there safely and make it easier to get through the gate quickly with smaller groups of people.

The threat from ISIS comes as President Joe Biden and his administration are facing criticism on how they handled the overall evacuation from Afghanistan.

The withdrawal, which was announced by Biden earlier this year, has been beset by multiple controversies, including people swarming the airport and making it almost impossible to get even some with the proper documentation out of the country.

The U.S. Embassy in Afghanistan on Saturday warned American citizens not to travel to the airport “because of potential security threats outside the gates at the Kabul airport.”

A White House official informed the press pool on Saturday, that, in the past 24 hours, six U.S. military C-17s and 32 charters departed Kabul. The total passenger count for those 38 flights is approximately 3,800. The White House official says that since Aug 14.the U.S. has evacuated approximately 17,000 people.

A White House official also informed the press pool that Biden met with his national security advisors Saturday morning. Those conversations focused on the current security situation and counter-terrorism operations in Afghanistan, including issues pertaining to ISIS. The larger-scale evacuation was also discussed, the White House said.