Porto have condemned an attack on coach Sergio Conceicao's family as they were driving away from the club's stadium after Tuesday's 4-0 home defeat by Club Brugge in the Champions League.
"FC Porto totally condemns the attack on coach Sérgio Conceicao's family car, last night, outside the Estadio do Dragao," the Portuguese club said in a statement on Wednesday.
"FC Porto also regrets the lack of protection from the authorities, and calls for the author or authors of this savage act to be quickly identified and held accountable."
Portuguese newspaper Record reported that Conceicao's wife Liliana was driving her 22-year-old son Rodrigo, who plays for Porto, and seven-year-old son Jose when her car was attacked by fans throwing rocks, breaking the windows.
The report added that the family was in a state of shock after the attack but did not suffer any injuries.
The loss to Brugge, Porto's third defeat in all competitions this season, left them bottom of Champions League Group B after two games.