CLEVELAND (AP) — NFL officials are investigating whether someone in the Cleveland Browns’ organization improperly sent text messages during games in violation of league rules.

NFL spokesman Michael Signora confirmed the investigation Friday and said the league was looking into whether the Browns violated rules governing coaching aids.

The rules prohibit smartphones and cellphones from being used in team areas, including sidelines and coaching booths from 90 minutes before kickoff and in locker rooms after kickoff. The restrictions on the devices end after games end.

Browns officials said in a statement that they are reviewing internally and will cooperate with the NFL in its investigation.