Pakistan is holding by-polls in four constituencies of the national and provincial assemblies today.
The vacant seats are from Punjab and Khyber Pakhtunkhwa.
Polling is being held under tight security and will continue till 5pm, according to the Election Commission of Pakistan.
All four seats fell vacant due to the death of former lawmakers.
The constituencies being contested are: NA-75, Sialkot-IV Daska, PP-51 Gujranwala I, NA-45 Kurram I and PK-63 Nowshera III.
The Daska seat was formerly occupied by PML-N's Iftikharul Hassan Shah and the Kurram seat by JUI-F's Munir Khan Orakzai.
In Daska, around 360 polling stations have been set up and the total number of voters is 44,003. The contest is between Syeda Nosheen Iftikhar of PML-N and Ali Asjad of PTI.
In Kurram, 27 candidates are contesting with the main competition expected among PTI's Fakharuzzaman Bangash, JUI-F's Jamil Khan and independent candidate Haji Syed Jamal.
The constituency has 134 polling stations for 180,931 voters.
Earlier this week, polling took place in the by-elections for vacant Sindh and Balochistan Assembly seats — PS-43 Sanghar III, PS-88 Malir II and PB-20 Pishin III.
PPP candidates had secured a victory in the Karachi and Sanghar by-polls, while a JUI-F candidate won the Pishin seat
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