Imran Khan's PTI 'wins revote' in tense Karachi
Imran Khan's party has won its first National Assembly seat in the Pakistani city of Karachi after a partial re-run of voting following rigging fears, unofficial results show.
The revote also saw the PTI take two provincial assembly seats, reports say.
The news came after Mr Khan blamed the murder of a senior party figure on Karachi's dominant party, the MQM, which has denied any involvement.
Thousands of MQM supporters rallied in the city to denounce Mr Khan.
The general elections on 11 May handed an emphatic victory to Nawaz Sharif and his Pakistan Muslim League-Nawaz (PML-N) party.
They ensured that Mr Khan's party became Pakistan's third-largest electoral force.
The vote also marked the first transition of power between democratically elected governments since the creation of the state of Pakistan in 1947.'Baseless'
On Monday, MQM protesters burned an effigy of Mr Khan, and attacked his character and Western lifestyle from his days as an international cricket star.
Khan supporters held a separate demonstration in the city. The party has urged the British government to take action against MQM leader Altaf Hussain.
He runs his party, and effectively Karachi, from his headquarters in north London where he has been based for more than two decades.
The election gave the MQM 16 out of 19 National Assembly seats in its stronghold, Karachi.
Mapping how Pakistan voted
Sunday's re-run took place amid tight security in 43 out of about 200 polling stations across Karachi's upmarket NA-250 constituency - the MQM boycotted the partial re-run.
The latest results show that Dr Arif Alvi of the PTI polled 77,000 votes and that the MQM's Khushbakht Shujaat was the runner-up with more than 30,000 votes.
Once confirmed, it will be the PTI's only National Assembly seat from Sindh province.
The party also appears to have won two provincial assembly seats from Karachi. Voting for these seats was also completed on Sunday.
Tensions peaked at the weekend over the killing of PTI vice-president, Zahra Shahid Hussain, who was shot dead outside her home by gunmen on a motorcycle.
Her funeral was on Sunday, the day repolling was held with a heavy police and army presence.
MQM spokesman Mohammad Anwar dismissed the accusations by Imran Khan, telling the BBC his comments were the "groundless, baseless" accusations of a man who had suffered a bitter, unexpected loss in the election and accused him in turn of behind the killing.
The MQM (Muttahida Quami Movement) is supported mainly by Muslim Urdu-speaking people whose families moved to Sindh province at the time of the partition of India in 1947.
Correspondents say that the party is seen as a perpetrator - as well as a victim - of violence in Karachi.
Since the 1980s, it has won every election it has contested there.
The projected victory for the PTI in this final assembly seat will not change the big picture in the city or in the country, correspondents say.
However, it will give the PTI an influential foothold in Pakistan's commercial capital, something the MQM will see as a major setback, particularly after results show that the PTI got the most votes in the city after the MQM.