KINSHASA, Democratic Republic of Congo — In the days after Congolese voters went to the polls late last month, as ballots were being counted, the opposition candidate widely believed to have won the presidency offered assurances to the regime that has long ruled the country.
“If I am elected, there will not be revenge,” said the candidate, Martin Fayulu.
Mr. Fayulu’s rival opposition candidate, who was handed victory by Democratic Republic of Congo election officials on Thursday, in a decision that has set the country on edge, may have done Mr. Fayulu one better.
The president-elect, Felix Tshisekedi, declared that his predecessor, President Joseph Kabila, who agreed to step down only with the utmost reluctance after 18 years, will be an “important partner” in the transition. Mr. Tshisekedi’s comment reinforced speculation that his campaign had reached some kind of power-sharing agreement with the Kabila government.
For his part, Mr. Fayulu protested the electoral commission’s decision, calling on Congolese to “rise as one man to protect victory.”
Independent observers have also questioned the legitimacy of the vote-counting, among them European officials and the National Episcopal Conference of Congo, a Catholic bishops group that sent 40,000 observers to voting stations across the country.
“We find that the results of the presidential election,” the bishops group said, do not “match the data collected by our observer mission.”
Now it is a matter of waiting.
On Thursday, Congo appeared generally calm, although the authorities said three people had been killed in a clash with Fayulu supporters in Kikwit, in the southwestern part of the country. Shops were vandalized by protesters, the authorities said.
As night fell, The Associated Press reported, scores of police officers with automatic rifles and tear-gas launchers were deployed along a road leading from Kinshasa, the capital, to Limete, a stronghold of Mr. Fayulu.
“We urge everyone to demonstrate civic maturity and above all avoid any recourse to violence,” the bishops group said.
Neither Mr. Tshisekedi nor Mr. Fayulu was the first choice of President Kabila, who had thrown his weight behind a top aide. But that candidate drew so few votes that Mr. Kabila and his allies pivoted to Mr. Tshisekedi, whom they regarded as less adversarial.
On Thursday, the electoral commission said Mr. Tshisekedi had received more than seven million votes to more than six million for Mr. Fayulu. The Kabila-backed candidate drew more than four million votes.
The United Nations Security Council is to meet on Friday to discuss the election outcome, which has been called into question by France and Belgium.
“The credibility of the elections will be there only if the Congolese themselves recognize this credibility,” Foreign Minister Didier Reynders of Belgium, one of the Security Council’s new members, told the Belgian radio station RTBF on Thursday.
António Guterres, the United Nations secretary general, issued a carefully worded statement acknowledging the provisional results and exhorting all Congolese to “refrain from violence.”
His spokesman, Stéphane Dujarric, declined to comment on whether he considered the outcome fair.
“We do not have a mandate or are in a position to bless or not bless these results,” he said.
President Kabila agreed to step down only after failing to come up with a way to circumvent term limits. He has not ruled out seeking a return to power.