Cardiff have suspended two members of their academy staff over bullying allegations.
The Sky Bet Championship club have launched an investigation, working closely with the Football Association and the English Football League, over what are described as "non-recent events".
"Cardiff City FC can confirm that it has launched a comprehensive investigation into non-recent allegations of bullying and poor practice relating to the club's Academy," said a club statement, which was published on the Bluebirds' website after 10pm on Friday.
"The club's head of safeguarding is conducting the investigation, in close liaison with the Football Association and the EFL and in line with the Affiliated Football Bodies process and statutory partner regulations.
"It is being overseen by the club's board of directors.
"As a result, two members of the club's Academy staff have been suspended whilst this internal process continues.
"Cardiff City Football Club takes all safeguarding reports extremely seriously and there are significant reporting mechanisms in place for these to be made, either via the club's safeguarding channels or those provided by national governing bodies and external support agencies."
Former Wales captain Craig Bellamy stepped down from his position as Cardiff Under-18s coach in January 2019 while the club investigated a bullying claim against him and others.
Bellamy denied the allegations against him and in June 2019 became the under-21 team coach of Belgian club Anderlecht.
Cardiff's investigation highlighted "a number of significant concerns" and concluded that academy players faced an "unacceptable coaching environment" at the club.