Shoppers at the V-Mall centre in Greenhills, San Juan were seen fleeing the building after a "disgruntled" security guard who recently lost his job took numerous people hostage.
Filmed today (March 2), the footage shows shoppers fleeing in panic.
Filmer Marco Subido was running errands and going to the bank while the scene unfolded.
Subido said: "I was aiming to find my way outside as I thought there was a mass shooter or terror attack inside.
Authorities have confirmed that at least one person has been shot.