The NFL outlined the league's gambling policy and called for federal assistance to address the "illicit sports betting market" in a response letter sent to a U.S. congresswoman Friday.

Alarmed by an uptick in betting-related controversies, U.S. Rep. Dina Titus (D-Nev.) in mid-June issued letters to commissioners and presidents of 12 prominent sports leagues inquiring about their gambling policies and efforts to protect the integrity of the games in the modern landscape.

Thirty-four states, the District of Columbia and Puerto Rico have launched legal betting markets following a ruling by the U.S. Supreme Court in 2018.

"There is no higher principle at the NFL than safeguarding the integrity of the game," Jonathan Nabavi, the league's vice president of public policy and government affairs, wrote in the response letter to Titus obtained by ESPN.

"Our efforts to uphold game integrity have been ongoing throughout the history of the league and our commitment has not wavered since the Supreme Court's decision. The increased accessibility of sports betting has made our efforts even more important."

The NFL has suspended 10 players in 2023 and 12 overall for violating the league's gambling policy since the Supreme Court struck down the Professional and Amateur Sports Protection Act of 1992, the federal statute that had restricted legal betting to primarily Nevada.

While legal sportsbooks have spread around the nation, the underground betting market remains prevalent, and the NFL believes the lack of safeguards with bookmakers who operate outside of the regulated environment in the U.S. poses an integrity threat.

"We believe that additional attention and resources are needed from lawmakers and law-enforcement to address the illicit sports betting market, which still has the power of incumbency," Nabavi wrote.

In addition to the suspensions in the NFL, collegiate sports has seen an uptick in betting controversies. This week, four current and past student-athletes at Iowa State, including Cyclones' quarterback Hunter Dekkers, and three student-athletes at the University of Iowa were criminally charged in a sports betting investigation.

NCAA President Charlie Baker, in a response to Titus on July 12, disclosed that there had been 175 sports betting violations since 2018 in NCAA sports.

"I agree with you that in addition to the opportunities it creates, sports betting brings risk that could undermine the integrity of competition," Baker wrote to Titus.

The Iowa Racing and Gambling Commission said Thursday it had not seen evidence of any game manipulation in the recent betting scandals at Iowa and Iowa State.