In a statement issued on Friday, he termed the incident an attack on the freedom of the Press.
Altaf Hussain said that the killings of journalists had created a sense of insecurity among the journalists' community.
He extended sympathies to the bereaved family members and journalists' organisations.
He appealed to the authorities concerned to take serious notice of the killing of Mahmood Afridi.
He said that the perpetrators should be brought to justice.