The Department of Homeland Security on Wednesday blasted major U.S. airlines for hastily restricting cooperation with immigration authorities amid the uproar over family separations at the border.

American Airlines, Southwest Airlines, United Airlines, and Frontier Airlines all condemned DHS earlier Wednesday and demanded that the government stop using their flights to transport children separated from their families -- even though they admitted they were not sure the government was, in fact, using their flights for that purpose.

But a DHS spokesman fired back, noting the flights can actually be used to reunite families.

"It’s unfortunate that American, United, and Frontier Airlines no longer want to partner with the brave men and women of DHS to protect the traveling public, combat human trafficking, and to swiftly reunite unaccompanied illegal immigrant children with their families," DHS Press Secretary Tyler Q. Houlton said in a statement.

The airlines were reacting in part to outrage that spread rapidly on social media after a recent Facebook post described 16 "sweet innocent" children who were "dressed as criminals" being loaded onto a domestic flight. The post fueled the already intense outcry over the practice of separating children from illegal immigrant parents -- a practice President Trump moved to reverse Wednesday afternoon via executive order.

The post, though, did not specify the airline and was a second-hand account. According to the post, purportedly from a flight attendant's coworker, the children were accompanied by an "adult escort" and had been "ripped from their families." The post also claimed the kids did not speak English and were "dressed in black and gray cheap Walmart sweat suits."

TRUMP SIGNS EXECUTIVE ORDER TO KEEP FAMILIES TOGETHER AT THE BORDER

The Association of Flight Attendants-CWA, which represents 50,000 flight attendants, reportedly claimed that the post was genuine but did not explain how it came to that conclusion.

According to the Arizona Republic, which analyzed the flight times described in the post, the alleged incident likely occured on an American Airlines flight.

"Buckling to a false media narrative only exacerbates the problems at our border." — DHS spokesman Tyler Houlton

But DHS officials, without specifically addressing the Facebook claim, reiterated that airlines are crucial partners in conducting important immigration-related services that protect children.

"Buckling to a false media narrative only exacerbates the problems at our border and puts more children at risk from traffickers. We wish the airlines would instead choose to be part of the solution.

"For 15 years, the Department of Homeland Security has worked diligently with America’s airlines to secure aviation and facilitate the travel by air of millions of Americans and visitors and we will continue to do so," Houlton added.

In rapid-fire statements, major U.S. airlines quickly and publicly had distanced themselves from DHS.

"Based on our serious concerns about this policy and how it's in deep conflict with our company's values, we have contacted federal officials to inform them that they should not transport immigrant children on United aircraft who have been separated from their parents," United Airlines CEO Oscar Munoz said.

"Based on some research we have done internally and public reports, we have not seen evidence these children have been flown on United aircraft," he added.

In a tweet, Frontier Airlines made a similar statement, while saying that it is unaware if its flights have been used to transport separated children.

"Frontier prides itself on being a family airline and we will not knowingly allow our flights to be used to transport migrant children away from their families. At this time, we are not aware if Frontier has been used for this purpose."

"The family separation process that has been widely publicized is not at all aligned with the values of American Airlines - we bring families together, not apart," American Airlines said, adding that "the government does not disclose information about the nature of the flights it takes or the passengers who are traveling."

Southwest Airlines echoed that message: "While we do not have evidence that tickets purchased for Southwest flights have been utilized to transport detained children, we do not wish to have involvement in the process of separating children from their parents. Therefore, we appeal to anyone making those types of travel decisions not to utilize Southwest Airlines." Alaska Airlines also made a similar statement.

The Trump administration's "zero-tolerance" immigration policy has referred far more adult border crossers for prosecution, in turn leading to family separations due to longstanding rules barring children from being detained with adults in those circumstances. Trump, though, signed an executive order Wednesday afternoon to allow children to stay with parents caught crossing the border illegally.

In a statement, Delta Airlines applauded Trump's move Wednesday.

"Delta’s mission is to connect people and we are against anything that runs contrary to that mission," the airline said. "Recent reports of families being separated are disheartening and do not align with Delta’s core values. We applaud the Administration’s Executive Order resolving the issue of separating children from their families at the U.S. border.”

Fox News' Ray Bogan and John Roberts contributed to this report.