UEFA have temporarily withheld prize money owed to Atletico Madrid and Malaga pending an investigation into their financial practices.

The Club Financial Control Body (CFCB) today announced that money owed to a total of 23 clubs across the continent had been held back as financial fair play rules kick in.

“As part of the first measure of the financial fair play requirements included in the UEFA Club Licensing and Financial Fair Play Regulations 2012, the clubs participating in 2012/13 UEFA club competitions had to provide information regarding the status of any overdue payables as at 30 June 2012,” reads the statement on UEFA's website.

“Following its last meeting in August 2012, the CFCB investigatory chamber has identified that important overdue payables towards other clubs, and/or towards employees or social/tax authorities existed in 23 cases.”

Europa League holders and UEFA Super Cup winners Atlético were one of the clubs named, as were Málaga, who have qualified for the Champions League group stage for the first time. Other notable names on the list include Sporting Lisbon of Portugal, Rubin Kazan of Russia and Fenerbahçe of Turkey.

The CFCB added that they will continue to investigate the clubs involved until the end of the month and will: “provide an updated situation as of 30 September 2012 with regards to overdue payables towards other clubs, employees and social/tax authorities.”

It is not yet clear what punishments Atlético and Málaga could face.

The Costa del Sol club have endured a difficult summer and been forced to sell key players, including Santi Cazorla and Salomón Rondón, after funding from their Qatari owners dried up.

Atlético are one of Spain's most indebted clubs and owed €155 million in unpaid taxes at the last count.