Royal Antwerp teenager Joel Lobanzo has died after suffering a cardiac arrest during a training session on Tuesday, the Belgian club have said.
Lobanzo, 17, collapsed while training with the under-19s on Tuesday and was taken to hospital, where he died during the night from Wednesday to Thursday.
"We discovered this terrible news that Joel Lobanzo, a 17-year-old youth player from RAFC, died last night," the club said in a statement. "The young football player had become a victim of sudden cardiac arrest during the training of the U19s on Tuesday night.
"The medical supervisor and trainers who were in the vicinity of the player immediately started resuscitation, after which the MUG team transferred the player to the UZA in critical condition.
"The young man remained in critical condition for more than one day, but sadly died during the night from Wednesday to Thursday.
"At the time of this tragic event, some tens of young people were present in the training fields. For all witnesses of this awful incident -- both fellow players, trainers and youth workers -- the club has provided shelter and support since yesterday.
"Over the next few days this will be the case. This is further communicated internally. For respect for Joel and his family, the club wishes to limit communication."
The statement said the club "strongly urge the media not to bother the family and friends" and added: "A time of mourning breaks, which we want to spend in serenity.
"We convey our deepest feelings of compassion to Joel's family and friends."
Royal Antwerp, who currently lie fifth in Belgium's top flight after 13 matches, have had a long-term partnership with Manchester United.
More than 30 players at various levels of the Old Trafford set-up have spent time with the Belgium club since the late 1990s.
They include Jonny Evans, who is now at West Brom, Ryan Shawcross - currently at Stoke - and John O'Shea and Darron Gibson, now at Sunderland.