The U.S. Department of Transportation (DOT) announced on Friday that it will investigate whether two airports violated federal law or transportation regulations by denying a contract to Chick-fil-A on religious grounds.

“The Department has received complaints alleging discrimination by two airport operators against a private company due to the expression of the owner’s religious beliefs,” DOT said in a statement. “FAA’s Office of Civil Rights has notified the San Antonio International Airport (SAT) and Buffalo Niagara International Airport (BUF) that it has opened investigations into these complaints.”

The San Antonio city council passed a motion on March 21 to approve the Food, Beverage and Retail Prime Concession Agreement with Paradies Lagardère for the San Antonio International Airport with the condition that Chick-fil-A be excluded from the agreement. Councilman Roberto Treviño, who initially made the motion against Chick-fil-A, claimed the fast food restaurant expressed “anti-LGBTQ behavior” and that the ban reaffirmed that San Antonio is a champion of “equality and inclusion.”

The prohibition came after a report noted that in 2017, Chick-fil-A donated nearly $2 million to the Salvation Army, Fellowship of Christian Athletes and the Paul Anderson Youth Home. The report asserted that the three charities were discriminatory against LGBTQ individuals.

The ban received massive backlash, with many citing religious discrimination. Republican Texas Rep. Chip Roy, who represents the portion of San Antonio where the airport is located, also slammed the decision as “rampant discriminatory action” and warned it may impact how he advocates for San Antonio while serving in Congress.

Texas Republican Attorney General Ken Paxton announced days later that his office will investigate whether the city’s action violates Texas state law. Paxton also penned a letter to Secretary of Transportation Elaine Chao urging she open a federal investigation to determine if the ban violated federal transportation regulations.

“When I announced my investigation of the City of San Antonio for its blatant discrimination against Chick-fil-A, I also brought this matter to the U.S. Department of Transportation’s attention,” Paxton told The Daily Caller News Foundation. “I had complete confidence Secretary Chao would recognize, as her office has today, that the City of San Antonio’s intolerant actions warrant investigation.”

“Blatant discrimination based on the religious beliefs associated with a company and its owners violates the Constitution and is inconsistent with both Texas and federal law,” he added.

Buffalo Niagara International Airport also canceled plans to open a Chick-fil-A days later despite the widespread criticism that the San Antonio airport received.

“FAA notes that Federal requirements prohibit airport operators from excluding persons on the basis of religious creed from participating in airport activities that receive or benefit from FAA grant funding,” DOT’s statement continued. “The findings of the investigations will be communicated to the complainants once the investigations are completed.”

Watch Metro Voice for updates on the Department of Transportation investigation.