Business tycoon Hakainde Hichilema on Sunday extended his lead in Zambia's hotly-contested polls, partial results showed, after the incumbent president cried foul.
This is the sixth time opposition politician Hichilema, who is 59, has run for the top job and the third time he has challenged 64-year-old President Edgar Lungu.
Lungu who has been in office for six years faced the electorate amid growing resentment about rising living costs and crackdowns on dissent in the southern African country.
Hakainde enjoyed the backing of 10 opposition parties at Thursday's vote under the banner of the largest opposition United Party for National Development (UPND).
Official results tallied by the Electoral Commission of Zambia on Saturday night from 62 out of 156 constituencies, put Hichilema ahead with 1,024,212 votes, compared to 562,523 for Lungu.
Results from a further 41 constituencies released Sunday, showed Lungu had garnered around 490,000 more ballots, but still trailed Hichilema who had bagged an extra 800,000 votes, according to an AFP count.
Final results should be released by early Monday at the latest.
The incumbent has cried foul before a winner is declared, claiming the election was neither free nor fair due to incidents of violence reported in what are traditionally Hichilema's stronghold.
"With polling agents having been attacked and chased from polling stations, we were reduced to competing in seven (out of ten) provinces," he said in a statement issued through the president's office.
'Victory in sight'
Hakainde, who is popularly referred to by his initials 'HH' on Sunday called for peace, tweeting: "With victory in sight, I'd like to ask for calm from our members and supporters".
"We voted for change for a better Zambia that's free from violence and discrimination," he wrote on Twitter.
"Let us be the change we voted for and embrace the spirit of Ubuntu (humanity) to love and live together harmoniously."
Parties that have backed Hichilema on Sunday scoffed at Lungu's "unsubstantiated" claims and urged him to concede.
"We ask you (Lungu) for once to act in a statesman-like manner by quickly conceding to your brother Hakainde Hichilema so that the process of handover and reconciliation of this nation can begin," Charles Milupi, chairman of the UPND Alliance told reporters.
International election observers have commended the transparent and peaceful organization of the polls, but condemned the restrictions on freedom of assembly and movement.
Security forces blocked Hichilema from campaigning in several areas, including the strategic Copperbelt Province, citing breaches of coronavirus measures and a public order act.
Lungu also deployed the military following pre-election clashes and reinforced the army presence in three provinces after two deaths were reported on election day.
Social media access, restricted in the capital Lusaka just as Hichilema cast his vote, was restored on Saturday following a court order.