TOKYO - The Japan Football Association has launched an investigation into four referees alleged to have been provided "sexual services" by the Korea Football Association, a source close to the matter said Sunday.

South Korean media reported Friday that around 10 overseas referees, who oversaw seven matches in South Korea between 2011 and 2012, received massages at parlors in Seoul, Ulsan and other cities, paid for with KFA corporate credit cards.

Related coverage: