A leading Pakistani politician was shot dead outside her home in Karachi on Saturday amidst an ongoing standoff over last week’s election. Zahra Shahid Hussain headed the women’s wing of the PTI, which took second place in the national vote. PTI leader Imran Khan had called for a revote amidst a wave of campaign-related violence. On Sunday, Khan accused Altaf Hussain, leader of the rival party MQM, of responsibility for Zahra Hussain’s murder.

Imran Khan: “I hold Altaf Hussain responsible for this murder. Whatever happens, I am firmly standing against this murder because it is not the first time it’s happened. It has happened several times before. They wait outside the house of their target, just like what happened with Zahra. I hold them responsible. They have issued two threats, one to the journalists and the other to our workers and supporters when they staged a protest.”

More than 150 people have been killed in the violence surrounding Pakistan’s election.