The Federal Aviation Administration says it's investigating decisions to exclude Chick-fil-A from airport concession contracts in San Antonio, Texas, and Buffalo, New York, over opposition to the fast-food chain owners' record on LGBTQ issues.

The San Antonio Express-News reports the FAA told San Antonio officials Friday it is investigating complaints the city-owned airport discriminated "against a private company due to the expression of the owner's religious beliefs."

In a statement shared with NBC News on Tuesday, the FAA confirmed that it received complaints that airport operators were discriminating against private companies over "religious beliefs."

"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 agency stated. "The 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."

Keisha Russell, an attorney at the First Liberty Institute, the legal group that filed a complaint with Transportation Secretary Elaine Chao over Chick-fil-A's airport exclusion, said her organization is "pleased that the FAA responded to our request by opening an investigation into San Antonio for its blatant, illegal religious discrimination against Chick-fil-A."

“American business owners should not have to suffer because they want to operate their businesses in accordance with their religious beliefs," Russell continued. "Few things are more un-American than government hostility against religion.”

Andy Segovia, an attorney for the city of San Antonio, said his office is reviewing the FAA's notice.

Chick-fil-A, an Atlanta-based restaurant chain, has faced opposition elsewhere over donating millions over the years to groups that oppose same-sex marriage.

In a statement sent to NBC News Tuesday afternoon, a Chick-fil-A spokesperson stressed the company is not involved with the FAA investigation.

“Recent coverage about our company continues to drive an inaccurate narrative about who we are. We are a restaurant company focused on food and hospitality for all, and we have no social or political stance," the spokesperson wrote. "We are grateful for all our customers and are glad to serve them at any time. We welcome and embrace all people, regardless of religion, race, gender, ethnicity, sexual orientation or gender identity.”

Texas lawmakers this month approved a bill that would prohibit cities from taking "adverse action" against an individual based on contributions to religious organizations.

Texas Gov. Greg Abbott has signaled he will sign the legislation.

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