Several injured as members of Christian community take to streets in Faisalabad, Lahore, Gujranwala.
Protesters take to the streets of Lahore, Peshawar and Karachi against the attack.
Ikramul Haq was hanged for killing a guard in 2001 during a sectarian attack at an imambargah in Jhang.
Police claims all three killed hailed from Bajaur and belonged to the Taliban's Mullah Fazlullah group.
Ikramul Haq was set to be hanged at Kot Lakhpat Jail early Thursday in connection with killing a man in an imambargah.
Sarwar will also establish telephonic contact with MQM chief Altaf Hussain during his visit.
PAT alleges 12 supporters have been killed; CM Shahbaz presides meeting over the incident.