Islamabad, Oct 16 (IANS): PTI chief Imran Khan was leading on six out of the seven National Assembly seats he is contesting after polling concluded on Sunday, as per unofficial results, media reports said.

Results continue to pour in after the end of polling for by-elections on eight National Assembly seats and three Punjab Assembly seats amid reports of sporadic violence and clashes across the country, The News reported.

According to unofficial results received so far, PTI was in the lead on six NA seats -- Mardan, Charsadda, Karachi-Lorangi, Peshawar, Nankana Sahib and Faisalabad -- while PPP was leading in Karachi's Malir and Multan.

Meanwhile, Khan's party was ahead in two constituencies of the Punjab Assembly - Khanewal and Bahawalnagar - while PML-N was in the first position in Sheikupura.

The country witnessed intense political activity as the polling started at 8 am and continued peacefully in some constituencies, with sporadic clashes in others. Scores of candidates contested for the seats up for grabs across the country.

Among the contenders is former Prime Minister Khan who is running for seven of the eight seats in the by-election.

The vote, he says, is a "referendum" on his popularity, The News reported.

As the polling process started, Khan asked the people in relevant constituencies to come out in large numbers to vote.

"This is a referendum for Haqiqi Azadi from the cabal of crooks. We are contesting against all of PDM, the Election Commission and 'namaloom afraad'," Khan said in a tweet.