Pakistan's election commission today demanded a signed apology from Pakistan Tehreek-e-Insaf Chairman and Prime Minister-in-waiting Imran Khan for violating the electoral code of conduct while casting his vote during the general election on July 25, according to a media report.

A four-member bench headed by the chief election commissioner heard the case against Khan, after the Election Commission of Pakistan (ECP) took notice of him publicly stamping the ballot paper in NA-53 Islamabad constituency, instead of going behind the voting screen to cast his vote in secrecy.

The cricketer-turned-politician's counsel Babar Awan, who appeared before the ECP today, submitted a written reply stating that his client did not intentionally stamp his ballot publicly, Geo News reported.

According to the reply, photos of Imran's ballot were taken without his permission. The curtain, used around the ballot for secrecy, had fallen due to the crowd inside the polling booth.

It further sought an end to the case and requested the ECP to issue notification for Imran's victory from NA-53 Islamabad.

The ECP, however, dismissed the reply submitted by Awan and summoned an affidavit from Khan apologising for the controversial vote casting complete with his signature, the report said.

The commission then adjourned the hearing till tomorrow, it said.

Imran, 65, had defeated former prime minister Shahid Khaqan Abbasi in NA-53 Islamabad constituency.

The electoral body has withheld notification of Khan's victory from the constituency in view of the pending case against the PTI chief for violating the electoral code of conduct.

According to Section 185 of the Election Act, a person can be given a six-month jail sentence and/or fine of Rs 1,000 for not casting their vote in secrecy, the report said.

On July 30, the ECP had sought a written reply from Khan, who has been nominated by the PTI as the next Prime Minister after the party emerged as the largest in the National Assembly in the election.

Khan had contested from five constituencies and had won from all of them. But the ECP has only granted him temporary permission to take oath as a Member of the National Assembly, pending the outcome of the case of violation of electoral code of conduct.