The administration of U.S. President Joe Biden agreed on Monday to grant Turkey’s Islamist President Recep Tayyip Erdoğan a “lead role” in providing security at Kabul’s Hamid Karzai International Airport after U.S. forces withdraw from Afghanistan in September, U.S. National Security Adviser Jake Sullivan said on Thursday.

Biden and Erdoğan met in Brussels on June 14 while in the Belgium capital to attend a North Atlantic Treaty Organization (N.A.T.O.) summit. During their closed-door meeting, the two leaders “had a detailed discussion of a potential Turkish mission to secure the airport” in Kabul, Afghanistan, once a coalition of U.S. and N.A.T.O. troops withdraw from the country on September 11, Sullivan told reporters during an on-the-record press call on June 17.

“The President [Joe Biden] and President Erdoğan agreed that they would work together to make this happen,” the U.S. national security adviser confirmed.

A reporter at Thursday’s press call referenced Turkey’s offer to “secure and operate the [Hamid Karzai] international airport [in Kabul] provided it receives what its defense minister called political, financial, and logistical support” and asked Sullivan if Biden’s administration had “any sense of what exactly Turkey would need to fulfill this task” and what the U.S. was “willing to give in terms of support.”

“President Erdoğan indicated he would need, as you said, certain forms of support to do that,” Sullivan said in response. “And President Biden committed that that support would be forthcoming. President Erdoğan expressed satisfaction with that, and the two of them tasked their teams just to work out the final details.”

“But the clear commitment from the leaders was established that Turkey would play a lead role in securing Hamid Karzai International Airport, and we are now working through how to execute against that,” the U.S. national security adviser added.

Another journalist asked Sullivan on Thursday if the Biden administration had a “plan B” in the event that Turkey fails to provide security for Afghanistan’s main international airport as promised.

“[W]e are obviously also conducting contingency planning in the event that either Turkey can’t proceed — although we have every expectation they will — or can only proceed in a more limited fashion,” Sullivan revealed.

“And without going into too much detail at this point because of the sensitivity of that contingency planning, I will say that it focuses on security contractors who have extensive experience in both static and dynamic security in Afghanistan. And that is what we are looking at as the alternative,” he added.

Continuing, Sullivan said:

We have scoped out what would be necessary to be able to confidently secure the airport in Kabul. And we feel that we would have an alternative, although we are very much focused right now on converting the President’s commitments to each other — President Erdoğan and President Biden — into an action plan that sees the Turks taking the lead at HKIA [Hamid Karzai International Airport].

“Turkey is the only reliable country to maintain the process there [in Afghanistan] after the US’ withdrawal [sic],” President Erdoğan told reporters at a press conference on June 13, one day before his meeting with Biden in Brussels.

Turkey is one of two N.A.T.O. member states, including Albania, with a majority Muslim population. Erdoğan leads Turkey’s Islamist ruling party, the Justice and Development (AKP) party. The Taliban, an Islamist Afghan terror group, issued a statement this month warning that Afghans should control “every inch of Afghan soil” and that it would consider any foreign soldiers remaining in Afghanistan after September 11, including Turkish troops, as “occupying forces” and treat them accordingly.