Last month, Radio Free Asia said that the Korean squad, apart from two foreign-based players, were subjected to "harsh ideological criticism" after they lost all three matches and conceded the most amount of goals by a team at the World Cup.
"We sent a letter to the football federation to tell us about their election of a new president and to find out if the allegations made by the media that the coach and some players were condemned and punished are true," FIFA President Sepp Blatter told reporters on Wednesday.
"We are doing this as a first step and we will see how they answer."
"There was an unconfirmed report that these players have gone through torture or something like that, but I can't confirm that.
"I haven't seen anything with my eyes or heard anything with my ears. Maybe this FIFA investigation can clear the air."
