Many have seen this election as Congo's first chance at a democratic, peaceful transfer of power since independence in 1960.
Some observers have suggested that President Joseph Kabila's government sought to make a deal as hopes faded for a win for ruling party candidate Emmanuel Ramazani Shadary, who received more than 4 million votes, or 23 percent.
Speaking to thousands of cheering supporters in Kinshasa, Tshisekedi paid his respects to Kabila, whom he described as "an important political partner". Martin Fayulu was chosen by the major opposition candidates after a meeting in Geneva in early November 2018.
Polls put Fayulu on 44%, at least 20 points ahead of Tshisekedi.
The election had been delayed for more than two years as many Congolese anxious that President Joseph Kabila would try to stay in power.More news: US Says China Willing to Buy More American as Trade Talks End
Fayulu immediately rejected the result.
"The influential Catholic Bishop's Conference, which fielded 40,000 observers, says the outcome of the much-anticipated vote is at odds with its tally".
Resident John Kabamba says it "may be a message that the publication (of the results) won't meet the expectations of the Congolese people".
On Wednesday, people in the capital Kinshasa went home early and locked their doors, while police were deployed in strategic locations in anticipation of protests and clashes in reaction to the results of the December 30 poll.
Antonio Guterres, the United Nations secretary general, said he "takes note" of the announcement and urged all parties to "refrain from violence and ... to channel any electoral disputes through the established institutional mechanisms".
Congo's ruling party responded angrily, calling the church's announcement "anarchist", and the electoral commission accused the church of "preparing an uprising".More news: Senate Democrats Consider Blocking All Legislation Until Shutdown Ends
Tshisekedi, 55, is the son of the late Etienne Tshisekedi, the face of the DRC's opposition for decades. He died previous year and his son has inherited his party, and with it a chance of winning power.
But he has never held high office or had management experience and is hobbled by the lack of his father's charisma.
While Nshole acknowledged the difficulties in manually counting votes, especially in remote areas, he warned that the longer the election results are delayed, the more that suspicion will grow among the Congolese people.
Kabila's second electoral mandate expired in 2016 and he only reluctantly called new elections under pressure from regional powers.
Congo's powerful Catholic Church has upped the stakes by saying it found a clear victor from data compiled by its 40,000 observers deployed to all polling stations.
Since his father founded the UDPS in 1982, the party has served as an opposition mainstay in the former Belgian colony - first under dictator Mobutu Sese Seko, then under Kabila's father Laurent-Desire Kabila, who ruled from 1997 until his death in 2001.More news: North Korean leader visits econ-tech zone in Beijing before heading home
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