A man entered an eatery in Paceville on Tuesday evening, grabbed a knife and a glass bottle from a table and started attacking people, police said.
The incident happened in Triq il-Wilġa corner with Triq id-Dragunara at 10.30pm.
The police said the attacker, who is Spanish, had to be tasered after he disobeyed police orders and was aggressive with the officers.
Once he was arrested, he was taken to Mater Dei Hospital for observation.
Police investigations established that before entering the establishment, the man had also damaged a Ford Focus driven by a 28-year-old man from Pakistan. He was not injured.
A medical team was called on site to assist three people - a man from Switzerland and two Italian men, who were allegedly attacked by the Spaniard. They were then taken to Mater Dei Hospital. The Swiss suffered grievous injuries, the Italians, slight.
Police are investigating and a magisterial inquiry is being held.