PML-N's Ameer Muqam was the only candidate to opt out of the September 4 presidential election as the deadline to withdraw nomination papers lapsed on Thursday.

Muqam, the PML-N's Khyber Pakhtunkhwa president, had earlier submitted his papers to vie for the presidential role alongside Pakistan Tehreek-i-Insaf's Arif Alvi, PPP's Aitzaz Ahsan and joint opposition candidate Maulana Fazlur Rehman.

However, prior to Thursday's deadline, Muqam contacted the Election Commission of Pakistan to withdraw his candidacy.

"I want to withdraw my nomination papers," said the PML-N leader whose decision leaves the polls on Tuesday a three-way battle.

How is the President of Pakistan elected

The Election Commission of Pakistan had announced on Thursday that the presidential election will be held on September 4 — five days before the expiry of the five-year term of President Mamnoon Hussain.

Under Article 41 (4) of the Constitution, election to the office of the president is to be held not earlier than 30 days before expiry of the term of the president in office.

The president is elected by an electoral college comprising members of the Senate, National Assembly and four provincial assemblies. Voting is held through a secret ballot.

As per the 1973 Constitution, Alvi's election to the National Assembly on the hotly contested NA-247 (Karachi) seat will stand null and void once he takes oath as the country’s president, because an elected member of the parliament cannot hold the office of the president of Pakistan.

Section 43(2) of the 1973 Constitution states:

The president shall not be a candidate for election as a member of Majlis-e-Shoora (Parliament) or a provincial assembly; and, if a member of Parliament or a provincial assembly is elected as president, his seat in Parliament) or ... the Provincial Assembly shall become vacant on the day he enters upon his office.