WASHINGTON — Transportation Secretary Sean Duffy warned the Mexican government Saturday that the US could deny flight requests from the country after its southern neighbor forced American cargo carriers out of Mexico City and took away slots for flights from American airlines.

The Trump administration official accused Mexico of breaking a bilateral aviation agreement in 2022 when it pulled American flight slots and forced the US carriers out of Benito Juarez International Airport — before ordering its government to disclose all flight schedules with the Department of Transportation.

Flights from American, Delta and United Airlines had previously been given slots at the Mexico City airport.

Duffy also mandated department-level approval for any Mexican large passenger and cargo aircraft coming from and going to the US.

“Joe Biden and Pete Buttigieg deliberately allowed Mexico to break our bilateral aviation agreement,” he said in a statement, with his agency claiming the move “left American businesses holding the bag for millions in increased costs.”

“That ends today. Let these actions serve as a warning to any country who thinks it can take advantage of the US, our carriers, and our market. America First means fighting for the fundamental principle of fairness.”

The US cargo carriers were told to relocate from the airport within 108 days — despite being placed there under the US-Mexico Air Transport Agreement signed onto during the Obama administration in 2015.

The construction that prompted the removal of American cargo carriers from Mexico City has yet to begin more than three years later, according to the Department of Transportation.

Mexico was the top destination for travelers leaving the US, according to statistics from the Department of Commerce’s National Travel and Tourism Office compiled in 2019.

Additionally, the transportation chief suggested the US would withdraw antitrust immunity from Delta and Aeromexico, citing “serious concerns about the long-term competitiveness of the U.S.-Mexico market” and saying its government’s actions have harmed airlines, consumers and trade.

That could end the carriers’ joint venture allowing for revenue sharing, common pricing and capacity management — but Delta would be able to hold its equity stake in Aeromexico and continue flying to and from Mexico.

“Mexico lacks a transparent and non-discriminatory slot allocation regime that adheres to international standards and applies consistently across the country’s airports,” the department said in an order served to Delta.

“The lack of a coherent slot allocation regime and the prospect of arbitrary action looming at any time raises serious concerns about the long-term competitiveness of the U.S.-Mexico market and the ability of the Department to depend upon the air services agreement as a mechanism to ensure adequate competition,” the order read.

“Mexico’s actions harm airlines seeking to enter the market, existing competitor airlines, consumers of air travel and products relying on time-sensitive air cargo shipments traded between the two countries, and other stakeholders in the American economy.”

The “tentative proposal” to end the agreement “would cause significant harm to consumers traveling between the U.S. and Mexico, as well as U.S. jobs, communities, and transborder competition,” Delta said in a statement.

“We are reviewing the series of DOT orders regarding Mexico’s adherence to the U.S.-Mexico Air Transport Agreement and look forward to working with the Trump Administration to resolve the issues raised in the orders,” the airline rep added.

Reps for Mexico’s foreign ministry did not immediately respond to a request for comment.