Secretary of Defense Lloyd Austin has ordered US commercial airlines to provide aircraft to expedite evacuation efforts from Afghanistan, the Pentagon said on Sunday.

The planes would not fly to Kabul, but would be used to transport those who have already been flown out to military bases in Europe and the Middle East. That would allow military aircraft to focus on operations in and out of the Afghan capital, the Pentagon said.

The Ministry of Defense activated the Civil Reserve Air Fleet, a nearly 70-year-old program created during the Berlin Airlift to support commercial airlines in a “major national defense emergency”. It is the third time that the CRAF has been activated. It was previously used in the early 1990s and early 2000s during the Iraq wars.

Activation applies to 18 aircraft: three each from American Airlines, Atlas Air, Delta Air Lines and Omni Air; two from Hawaiian Airlines; and four from United Airlines.

The first United Airlines flight under CRAF took off on Sunday from Frankfurt-Hahn Airport to the Al Udeid Air Force Base in Qatar.

“The CRAF activation provides the Department of Defense with access to commercial air mobility resources to aid our State Department assistance in evacuating US citizens and personnel, special immigrant visa applicants, and other vulnerable individuals from Afghanistan,” Pentagon press secretary said John Kirby in a statement.

Foreign Minister Antony Blinken spoke to Bahraini Foreign Minister Abdullatif bin Rashid al-Zayani on Sunday and expressed his gratitude to Bahrain for the government’s humanitarian assistance in facilitating the safe transit of US citizens and evacuees from Afghanistan.

The US withdrawal from Afghanistan, announced earlier this year by President Joe Biden, has been ravaged by chaos. Thousands of people flooded Kabul airport, some falling to their deaths after holding onto the outside of a U.S. military plane in desperate attempts to leave the country after the Taliban took over the city and secured control of the country last week had.

Seven Afghan civilians were killed trying to enter Kabul airport, according to an Associated Press report.

US Defense officials say the military is looking for alternative ways to get Americans, Afghans and third-country nationals safely to the airport in Kabul after threats from the Islamic State, NBC News reported on Saturday.

“The department does not expect this activation to have a major impact on commercial flights,” said Kirby.

United Airlines said it will use four of its 350-passenger Boeing 777-300 aircraft for the CRAF order. The Chicago-based airline said it is still gauging the impact on its operations but that it will likely be minimal.

United’s flight attendant deals on CRAF flights began Saturday, according to a statement from their union. Crews receive an additional payment for these flights.

U.S. airlines have used some of their largest aircraft for domestic flights, with international travel demand still falling sharply due to the Covid-19 pandemic.

“We take on a responsibility to respond quickly to international challenges like these and to use our expertise to ensure the safe travel of our compatriots and those who risked their lives to ensure their safety,” United said in a statement.

Delta said it will “have several relief flights arriving in the United States starting Monday morning.” The airline said it was deploying replacement aircraft and commercial flights were not currently affected.

American Airlines announced that it will be using three wide-body aircraft for CRAF from Monday.

“American will work to minimize the impact on customers as the airline temporarily takes these aircraft out of our operations,” it said in a statement. “The airline values ​​customers’ patience and understanding when it comes to accommodating flights.”

Atlas Air, a cargo company and one of the airlines that fly for Amazon’s Air Force, regularly provides air transportation to the U.S. military. The company’s passenger fleet includes Boeing 747-400 with 374 passenger seats and 767-300 with 215 passenger seats, according to its website.

“We are doing as much as possible to provide the much-needed capacity to support the evacuation effort,” said an Atlas spokeswoman.

U.S. airlines volunteered planes earlier this week to assist with evacuation efforts, according to people familiar with the matter. The Pentagon did not immediately comment on whether it would consider expanding the program beyond the 18 commercial aircraft.