Supporters of Martin Fayulu, runner-up in Congo's presidential election, chant slogans and carry placards as he delivers his appeal contesting the election outcome. (Kenny-Katombe Butunka/Reuters)

In an unprecedented move, the African Union called on Congo’s government to suspend proclamation of the final results of the country’s Dec. 30 election, stating that it had “serious doubts” about their veracity.

The continental body also urgently dispatched a delegation to Congo’s capital, Kinshasa, to meet with election officials.

The rebuke from the normally cautious African Union comes amid mounting evidence that Congo’s election commission perpetrated massive vote fraud in the declaration of provisional results last week. The Independent National Electoral Commission, known as CENI, declared opposition candidate Felix Tshisekedi the winner with more than 38 percent of the vote.

Leaked data from CENI and the National Episcopal Conference of Congo — the largest election observation mission, led by the Catholic Church and known as CENCO — point to a resounding win for a different opposition candidate, Martin Fayulu.

Tshisekedi and ruling-party candidate Emmanuel Ramazani Shadary did not pass the 20 percent mark, according to the leaked data.

Fayulu has challenged the provisional results in Congo’s Constitutional Court in a case expected to be resolved Saturday. The African Union’s statement appears to be timed to put pressure on the court and to suggest it delay its decision.

Should the court dismiss Fayulu’s claims, which are backed by the leaked data, Tshisekedi would be inaugurated as president within 10 days. If the judges side with Fayulu, they could order a recount or a new election — a daunting task in a country that struggled to organize December’s election, even with years to prepare.

Congo’s government responded to the African Union statement on Friday afternoon, rejecting any further delay in announcing the results. Spokesman Lambert Mende told reporters that “the independence of our judiciary is no problem,” but “we will not refuse contacts with other members of the African Union.”

Tshisekedi’s camp has vowed to release its own polling data, though not until Sunday, after the court was expected to announce its decision.

The election was considered historic as it represented Congo’s first chance at a peaceful, democratic transfer of power. It also was billed as marking the end of 18 years of rule by Joseph Kabila, who is accused of vast corruption.

So far, the country has remained more peaceful than expected — though there have been scattered and deadly clashes between opposition supporters and state security forces. But widespread reports of irregularities and voter intimidation, as well as the leaked data and the ongoing court challenge, have raised major doubts about the election’s democratic integrity.

The Congolese government has shut down Internet connections and text-messaging services across the country since the day after the election — ostensibly to prevent the sharing of fake results.

Many in the opposition have accused the government of maintaining the shutdown for the opposite purpose — to suppress a reaction to its own ma­nipu­la­tion of the election in favor of Tshisekedi after it became clear its candidate, Shadary, lacked support.

“We reiterate our call for a recount. We thank the African Union for its ongoing efforts in favor of truth and justice in the Democratic Republic of Congo,” Fayulu said on his Twitter account.

The African Union announcement was starkly different from one issued by the smaller Southern African Development Community. “We believe that the situation in the DRC has been managed and handled well and international constitutional processes are ongoing,” the SADC said. “Any electoral grievances must be addressed in line with the DRC constitution and relevant electoral laws.”

The African Union statement was particularly surprising because it was issued after a meeting of African leaders, many of whom have been in power for decades and openly suppress democracy in their countries. The meeting that produced the announcement was chaired by Rwandan President Paul Kagame and included Uganda’s Yoweri Museveni, Chad’s Idriss Déby and the Congo Republic’s Denis ­Sassou-Nguesso. Those four leaders’ combined years in power come to more than 100.

“The African Union traditionally defers to the subregion. But here it practically contradicted SADC’s much blander stance, intervening in an electoral dispute of a member state,” said Jason Stearns, a director of the Congo Research Group at the Center on International Cooperation, a New York University-based think tank.

Stearns’s group published the leaked data, as did numerous Western publications such as the Financial Times and Radio France International. Congolese news outlets followed up with verifications of the data.

The data sets were obtained from whistleblowers within CENI, as well as CENCO and Fayulu’s campaign. The CENI data represented 86 percent of the votes counted, and CENCO’s represented 43 percent.

Stearns said it was “extremely unlikely” that the leaked data sets were fake, as they were almost identical, and a coordination between CENCO’s observers and Fayulu’s campaign would have had to take place “without anyone knowing about the scheme.”

Congo’s Catholic Church has traditionally been aligned with the opposition.