The bishops of the Democratic Republic of the Congo are among several major observers casting doubt on the results of the nation’s Dec. 30 presidential elections.

“[T]he results of the presidential election as published by the CENI [National Election Commission] do not correspond to the data collected by our observation mission from the polling and counting stations,” said the standing committee of the DRC bishops’ conference in a Jan. 10 statement.

Overnight, the National Election Commission announced that opposition party leader Felix Tshisekedi had won the presidential election with 38.57 percent of the vote, just surpassing former oil executive Martin Fayulu, who had 34.8 percent.

The two major opposition candidates both finished well ahead of former interior minister Emmanuel Ramazani Shadary, who had been officially backed by outgoing President Joseph Kabila but had never gained traction during the campaign.

The Congo bishops’ conference did not say which candidate their data showed winning the vote. However, Fayulu has claimed that he is the rightful winner and has suggested that Tshisekedi had made a power-sharing deal with outgoing president Kabila to rig the election.

Kabila has spent the last 17 years in power. While the nation’s term limits required the president to leave office in 2016, he refused to step down.

The bishops of the country, who have played a key role in promoting democracy, had helped mediate the 2016 New Year’s Eve Agreement between the country’s ruling political coalition and opposition leaders. Under the agreement, Kabila was allowed to remain in office past his mandate but agreed to step down after an election in 2018

The bishops’ conference had also commissioned more than 40,000 election observers, who were sent to polling stations across the country to report on the election process.

In a Dec. 31 statement, the bishops’ conference had voiced concern about voting irregularities, including registered voters who were turned away from polling stations because their names were not on voting lists and election observers being expelled from polling stations by police officers.

Conference officials also noted that an estimated 1 million people were unable to vote due to a deadly Ebola outbreak in some regions of the nation, with voting in some affected cities delayed until March, well after the new president is scheduled to take office.

Other election observers also reported irregularities including voting machine malfunctions, polling stations opening late, locations being changed on short notice, and an inability to cast votes privately, according to the BBC.

The bishops’ conference had delayed the release of its preliminary observation after internet connections and text message services were shut down across the country on Dec. 30.

Reuters has reported that observers from France and Belgium have also voiced doubts that Tshisekedi won the election, and three diplomats who had reviewed the Church’s observer mission data said Fayulu had won.

In his first remarks after his victory was announced, Tshisekedi promised to work closely with Kabila, AFP reported.

“Today we should no longer see him as an adversary, but rather as a partner for democratic change in our country,” he said to supporters.

Tshisekedi, 55, leads the Union for Democracy and Social Progress (UDPS), the country’s oldest and largest opposition party. He inherited leadership of the party when his father – a longtime advocate for democracy – died in 2017. His inauguration is scheduled for Jan. 18.

The 2018 election was a major test for the volatile nation, which has been plagued by political corruption, instability, and violence throughout its history, and has never seen a peaceful transition of power.

At least four people have been killed so far in scattered protests of the election results.

The bishops in their Jan. 10 message stressed the need for “civic maturity” and avoidance of violence.

“In the event of a possible challenge to these provisional results by a party, we urge it to use the legal means in accordance with the Constitution and the electoral law,” they said.