UEFA has ordered a deeper investigation into Turkish champion Galatasaray's spending.

Galatasaray joins Paris Saint-Germain among Champions League clubs this season under extended scrutiny for possible "Financial Fair Play" breaches. The rules require Champions League and Europa League clubs to approach break-even on soccer-related business.

Though UEFA investigators reached agreement with Galatasaray in June, the finance panel's judges decided to "refer the case back ... for further investigation."

The settlement remaining in force during the case includes Galatasaray paying 6 million euros ($6.9 million) from UEFA prize money and limiting its Champions League squad to 21 senior players instead of 25.

Critics say UEFA's rules protect storied clubs with global brands from high spending by ambitious rivals.

Galatasaray is currently third in its group behind Porto and Schalke.