Sabri performed Qawwali devotional music from the Sufi tradition, an Islamic practice opposed by religious extremists.
Ahead of his funeral, mourners have gatd outside his home in Karachi.
T have also been demonstrations overnight in Lahore and Islamabad, condemning such violence.
Sufism, a tolerant, mystical practice of Islam, has millions of followers in Pakistan but is opposed by extremists.
The Taliban, who view Sufism as tical, have been blamed for previous assaults on targets linked to Sufi Islam.
It is not known if the shooting is related to that incident.