The incident took place in the early hours of Sunday morning during local festivities for the city. Newspaper i reports that the young boy, who is believed to be aged around three, started feeling unwell after touching a lamp post that had been erected purposely to illuminate the party venue.
A PSP source told the newspaper that the child had been accompanied by his father and had become lifeless after touching the pylon and having convulsions.
He was taken to the Beatriz Ângelo hospital in Loures but died a short while later. An investigation is ongoing.