The Biden administration has ordered the use of commercial airlines to help transport tens of thousands of evacuees from Afghanistan, as the United States seeks to accelerate the pace of departures of Americans and at-risk Afghans from the country.

The activation is the third time the U.S. has mobilized what is referred to as the Civil Reserve Air Fleet (CRAF), leaning on the fleet the government last called on during the Iraq War in 2003 as Washington expands the number of U.S. military installations that could house Afghans, reports said.

Some 18 commercial jets will be used in the evacuation, including four from United Airlines, three from Delta Air Lines, three from American Airlines, three from Atlas Air, and two from Hawaiian Airlines.

The Pentagon announced Sunday that U.S. Defense Secretary Lloyd Austin ordered the commander of the U.S. Transportation Command to carry out Stage 1 of its CRAF to help in ferrying Americans, assist in processing Special Immigrant Visa applicants and other vulnerable individuals out of Afghanistan, CNN reported.

The passenger aircraft will not fly into Kabul's international airport, Pentagon press secretary John Kirby said but will transport people from temporary safe havens and staging locations like Qatar or Germany to the U.S. or a third country.

The airlines will be compensated as part of the deal, Kirby said, as the Pentagon "doesn't expect a major impact to commercial flights" as a result of mobilizing the fleet, Fox Business reported.

Scenes of mayhem continue at the Kabul international airport a week after the Taliban overran the city. On Sunday, thousands of people remained outside the airport, hoping to be evacuated as the Taliban fighters beat back crowds.

The U.S. advised Americans in Kabul not to travel to the airport. Officials told U.S. outlets there were worries Islamic State militants might launch an attack.

U.S. State Secretary Tony Blinken told CBS's "Face the Nation" that the government has already evacuated around 8,000 people over the last 24 hours. They have "gotten about 30,000 people out between our military flights and the charters that we have organized" since July, Blinken said in quotes by The Guardian.

U.S. President Joe Biden said Sunday his administration may extend an Aug. 31 deadline for the pullout of American forces from Afghanistan. White House press secretary Jen Psaki said Biden would meet via live stream with Group of Seven (G7) leaders on Tuesday.