The electoral commission (CENI) announced around 3.00 a.m. (0200 GMT) that opposition leader, Felix Tshisekedi, 55, had won the December 30 vote, edging out another opposition candidate, businessman Martin Fayulu.
His fellow opposition candidate Felix Tshisekedi was declared the victor of the December vote by the electoral commission early Thursday morning.
Several diplomats briefed on the matter told The Associated Press that the figures compiled by the Catholic Church showed that Fayulu won an absolute majority of the votes. The discrepancy sets the stage for a possible standoff between the Congolese government and the Church, which deployed 40,000 election observers and is considered one of Congo's most influential and trusted institutions.
There are widespread concerns that a contested result could spark unrest.
He will take office from President Joseph Kabila, who has ruled the resource-rich central African country since 2001.
Fayulu can appeal the results to Congo's constitutional court but has not yet indicated whether he will.
The Chairperson of the Commission reiterates his congratulations to the people, political actors, civil society and the relevant national institutions of the Democratic Republic of the Congo for the conduct of the elections under conditions deemed satisfactory by the African Union Election Observation Mission led by President Dioncounda Traoré.
About 40% of DR Congo's population is Roman Catholic and the church has a wide network of schools and hospitals.
Mr. Apea asked all institutions in the DRC, from "the sacred to the secular", to respect the results of the Electoral Commission of the DRC and let peace prevail.
The difference between Tshisekedi and Fayulu in official results was some 684,000 votes. The United States threatened sanctions against officials who rigged the vote.
Tshisekedi "owes his ascendancy to power to Kabila's control of the electoral commission", and in exchange Kabila would look for immunity from any prosecution or asset seizure after handing over power, Besseling said.
The result if confirmed would create the first orderly transfer of power since independence from Belgium in 1960.
Defiantly, tens of thousands of voters in one of the barred communities held their own ballot on election day.
The government has cut internet service since the day after the election to prevent speculation on social media about who won, and blocked some radio stations. As the electoral commission met this week, anti-riot police moved into place outside.
"They have stolen the Congolese people's victory and the people will never accept that".
Some said they would be happy as long as Fayulu or Tshisekedi won, while recalling the violence that followed past disputed elections.
"Nobody knows how he would be able to cope with the position of president", Patta said of Tshisekedi.
A two-year wait for a new leader is coming to an end in the Democratic Republic of the Congo, but already a post-election crisis is brewing.
Felix Tshisekedi gestures as he is surrounded by his wife, relatives and supporters of his UDPS party (Union for Democracy and Social Progress), a few minutes after he was declared victor. He was less visible in campaigning than Fayulu and did not make himself available to reporters after the vote.
The candidate from Mr Kabila's party had initially been expected to win, but ended up finishing third - and is not challenging the results.
Pierre Englebert of the African Arguments newsletter said analysis of survey data "suggests that the probability Tshisekedi could have scored 38 percent in a free election is less than 0.0000".