Fifteen people were arrested in Istanbul on Thursday in connection with an ongoing police operation into alleged match-fixing in Turkish football.

Among those arrested was Sekip Mosturoglu, the deputy chairman of Turkish champions Fenerbahce, and Bulent Uygun, the manager of Eskisehirspor.

Fenerbahce Chairman Aziz Yildirim refused to make a statement to police and is being taken to the Istanbul court investigating the scandal. Another 11 people are currently in court, according to local press reports.

The police released a statement on Wednesday stating that there was concrete evidence that 19 football matches were fixed last season in the Turkish 1st and 2nd leagues.

The match-fixing scandal came to light when police launched operations in more than a dozen cities across Turkey and detained more than 50 people.