In a speech in the newly-constituted National Assembly, Bilawal requested the PM-elect, Shehbaz Shareef, to constitute an investigation commission headed by the top judge to probe the May 9 incidents.

Bilawal said the PTI, under Imran Khan, has repeatedly shunned negotiations with other political groupings, restricting prospective alliances.

"At several polling stations in the constituencies, including those of PML-N supremo Nawaz Sharif, his brother Shehbaz Sharif and daughter Maryam Nawaz the polling even began without the presence of the polling agents of the PTI in Lahore," party leader from Lahore Wasim Ahmad stated. 

Pakistanis will vote on Thursday to elect a new government to rule the cash-strapped country amid a spree of violence including deadly blasts on the eve of elections in which the front-runner former prime minister Nawaz Sharif is believed to have the backing of the powerful military.