Four lawmakers of Imran Khan's party today resigned from the Sindh assembly, stepping up pressure on Pakistan Prime Minister Nawaz Sharif to step down.  

Members of the Sindh provincial assembly belonging to PakistanTehreek-i-Insaf submitted their resignations to the assembly secretariat. The four PTI lawmakers followed in the footsteps of their31 colleagues in the national assembly and 29 in the Punjab assembly who have also sent in their resignations after cricketer-turned-politician Imran Khan asked them to quit.   

Syed Hafeezuddin, Samar Ali Khan, Seema Yazdani Zia and Khurram Sher Zaman tendered their resignations in the Sindh assembly.   

The resignations came as more protests and sit-ins were staged in Karachi by PTI workers, disrupting traffic flow in Pakistan's biggest city.