PTI wins at least 116 out of 272 National Assembly seats but, monitors say election not fought on a level playing field.
Islamabad, Pakistan - Imran Khan's Pakistan Tehreek-e-Insaf (PTI) has emerged as the single largest party in the Pakistani lower house of parliament, as international observers declared the polling process less fair than the country's previous general election.
The PTI won at least 116 out of the 272 directly elected National Assembly seats in Wednesday's election, official results released by the Election Commission of Pakistan (ECP) showed on Friday - with results from four constituencies still awaited.
Khan's party will need 137 seats to form the government, and has begun approaching smaller political forces with the aim of putting together a coalition.
With 64 seats, imprisoned former Prime Minister Nawaz Sharif's Pakistan Muslim League-Nawaz (PML-N) will almost certainly be relegated to the role of opposition for the next five years.
The Pakistan People's Party (PPP) won 43 seats, with independents and smaller parties taking the remaining seats.
Voter turnout was reported to be 51.78 percent of the more than 105 million eligible voters, a slight drop from the 2013 general election.
Polling was suspended in two constituencies after violent attacks during the campaign, and elections will be held there at a later date.
The PML-N on Friday led a multiparty conference in the capital, Islamabad, after it and several other parties - including the PPP and religious party coalition Muttahida Majlis-e-Amal (MMA) - alleged widespread irregularities in the vote-counting process.
Those in attendance rejected the election result, according to Fazl-ur-Rehman, Jamiat Ulema-e Islam (JUI-F) party chief. Other parties, including the PML-N, said they had not yet decided whether to join the JUI-F's call for nationwide protests.
On Thursday, Khan said his party would fully support any investigation into the allegations of poll rigging.