"Everyone is completely distraught. The players are in a terrible state," Allofs said.
Allofs later told Sky television: "Everybody loved him."
Wolfsburg coach Dieter Hecking struggled to hide his grief and fought back tears at Sunday's press conference.
"Junior was an exceptional young player - talented and full of life. He leaves a big gap," Hecking said.
Several hundred fans gathered to express their sorrow with a silent march on Sunday. Many left flowers, candles, pictures, and banners in the club's green and white colors at Wolfsburg's stadium, where the club opened a book of condolences for the young player.
Malanda was considered one of Belgium's top prospects. He played at every youth level for his country from under-15s to under-21s.
"Heaven is now your playing pitch, but we will not forget you," the Belgian Football Association said on its website.
Malanda scored two goals and set up four more in 17 Bundesliga games for Wolfsburg, which he joined from Belgian Pro League side Zulte Waregem in January 2014. He previously played for the reserve side of French club Lille, which he joined as a 12-year-old from Belgian side Anderlecht's youth setup.