At least 18 of 21 suspects have been arrested in Turkey as authorities intensify an investigation into alleged betting on top-tier football matches. The arrests came just a week after the Turkish Football Federation (TFF) suspended 149 referees and assistant referees over similar allegations.

According to state-run Anadolu news agency, Turkish prosecutors have issued arrest warrants for several referees, assistant referees, and the chairman of an unnamed Super Lig club. Coordinated early morning raids across Istanbul and 11 other provinces led to the detention of 17 referees and other suspects.

The Istanbul Chief Prosecutor’s Office stated that those arrested are being investigated for potential charges, including “influencing the outcome of a match.”

The scandal follows a TFF-led investigation that uncovered evidence of widespread betting activity among officials working in Turkey’s professional football leagues. TFF President Ibrahim Hacıosmanoğlu described the unfolding events as a “moral crisis in Turkish football.”

In a joint statement released on Wednesday, several referees dismissed the allegations as “outrageous accusations,” maintaining that none of them placed bets on matches they officiated. Some added that their betting activities occurred during their time as amateur referees.

The investigation marks one of the most extensive corruption probes in Turkish football history, raising fresh concerns about integrity and oversight in the sport.