Mr Khan, who has led a relentless anti-graft campaign, had the momentum heading into the election, and is seen as the military's top choice for prime minister despite his denials. On that front, he underscored the importance of trade ties with India. "The people of Afghanistan need peace, and Pakistan wants peace in Afghanistan", he said.
"I wish someday the two neighbors have an open border", he said.
About America, he said his government would look for a balanced relationship with its former ally in so-called war against terrorism. "So, the challenges are huge but they can only be done ... if we change the way we do governance in this country". "Accountability will begin from us and then trickle down". "We have to cope with this all", he added.
Gilani said many remain undecided: "It's still up for grabs".
Early voting was heavy at some polling stations in Islamabad, the capital, and also in the Punjab provincial capital, with several political party leaders standing in line to cast their ballots.
Khan's PTI, according to unofficial results, is leading on 119 seats out of total 272 general seats of the lower house- the National Assembly- slightly behind a simple majority.
Sharif's Pakistan Muslim League-Nawaz (PML-N) was ahead in 66 constituencies, and the Pakistan Peoples Party (PPP), led by the son of assassinated two-time prime minister Benazir Bhutto, led in 39 constituencies.
Also Wednesday, shooting between supporters of two opposing political parties killed one person and wounded two in a village near the northwestern city of Swabi.
A majority of 137 seats is needed to form a government.
His brother Shahbaz is leading the party's campaign.
Sharif, who was immediately placed in custody after returning from Britain almost two weeks ago, has denounced the verdict as politically motivated and accused a covert military-judiciary alliance of trying to keep him out of politics and undermining the integrity of his PML-N party.
Shehbaz and Bilawal, however, managed to win from other seats. The election in Pakistan this year will be one of the most-watched elections in the country's history. But that year, the PPP won more seats and went on to form the government at the centre.
Election Commission of Pakistan (ECP) secretary Babar Yaqoob told reporters early on Thursday counting had been delayed by technical failures in an electronic reporting system and the tallying was now being conducted manually.
Requesting the ECP to extend the polling time, under section 70 of the Election Act 2017, the PML-N has said that "we are receiving complaints on a large scale nationwide and PML-N would appreciate if this demand of the voters is accepted".
"These elections were 100 percent transparent and fair".
"Claims of election rigging occur after every election in Pakistan - but this time around, they will be harder to brush aside given the overt role the military has played", said Ms Shamila Chaudhary, a former White House and State Department official who is now a fellow at Johns Hopkins University School of Advanced International Studies.
He said the party was due to meet on Thursday to decide a way forward.
"I came into politics because I wanted make Pakistan a country that Jinnah had envisioned".
"This is not an election, but a selection".
The report also mentioned that election agents were not allowed to enter polling booths in Nawabshah, in the Sindh province, thus resulting in a delay in voting.
In an early-morning press conference, the Election Commission rejected the charges, saying it did "our job right".
"I want to warn that this type of actions will be detrimental for the national integrity and the democracy", he maintained.
The democratic transition is taking place at a time when Pakistan's economic troubles are deepening and foreign exchange reserves are depleting quickly.
On allegations of "blatant rigging" by PML-N, PPP and other parties, Khan said he is ready for any kind of investigation into the claims by the opposition. "The people of Pakistan will not accept that", Hussain charged without naming the PTI.More news: All duck boat sinking survivors out of hospital