The people should combat political intolerance which in the past led to the murders of Karin Grech and Raymond Caruana, PL leader Joseph Muscat said.
Speaking during a ceremony at the Karin Grech monument in San Gwann, Dr Muscat said that innocent blood had been shed in both these incidents.
Karin's father Edwin, thanked those who took part in the ceremony, remembering the 32nd anniversary of his daughter's death.
15-year-old Karin died when she opened a letter bomb addressed to her father during the doctor's strike in 1977.