Muttahida Qaumi Movement (MQM) chief Altaf Hussain has strongly condemned the murder of Pakistan Tehrik-e-Insaf (PTI) leader Zehra Shahid Hussain.Altaf Hussain termed the PTI leader's killing a barbaric act. He offered condolences over the killing with Zehra Shahid's family and the workers of the PTI, said an MQM press release received here on Saturday night.He prayed to Allah Almighty to rest the departed soul in eternal peace and grant fortitude to the bereaved family.Altaf Hussain called for arrest of the killers of the PTI leader.