The 17-year-old, who is understood to be of African origin, received a number of stab wounds at the centre on Sarsfield Street at 2.15pm.
He was taken to the Mid Western Regional Hospital where he died a short time later.
An 18-year-old man has been arrested and is being questioned by gardaí at Henry Street Garda Station.
He can detained for up to 24 hours.
A post mortem on the body of the dead teenager is expected to be carried out tomorrow.
Gardaí have begun an investigation in the circumstances of the young man's death.
