KINSHASA, Congo — Congo’s powerful Catholic church challenged the surprise win of opposition leader Felix Tshisekedi in the presidential election on Thursday, saying official results do not match the outcome compiled by its 40,000 observers at all polling stations across the troubled country.

The church refused to name its “clear winner,” but diplomats briefed on its findings said opposition leader Martin Fayulu won easily and that other election observer mission found similar results.

Fayulu alleges that President Joseph Kabila engineered a backroom deal with the largely untested Tshisekedi to thwart anti-corruption efforts in a country with staggering mineral wealth. An outspoken campaigner against Congo’s widespread graft — it ranked 161th among 180 countries in Transparency International’s latest index — Fayulu denounced the official vote results as “rigged.” He called on people to “rise as one man to protect victory.”

But the country remained largely calm as many Congolese appeared to accept the country’s first peaceful, democratic transfer of power. Tshisekedi’s supporters with Congo’s most prominent opposition group took to the streets in jubilation.

It was not immediately clear whether Fayulu would challenge the election results in court. Candidates have two days after the announcement to file challenges and the constitutional court has seven days to consider them before results are final.

Careful statements by the international community did not congratulate Tshisekedi, merely taking note of official results and urging peace and stability in a country with little of it. Observers appeared to be watching to see how Fayulu’s supporters reacted.

Two diplomats also said all major observation missions, including those of the African Union and the Southern African Development Community, showed similar results to those of the Catholic Church. The diplomats spoke on condition of anonymity because they were not authorized to speak to the press.

Tshisekedi, who received 38 percent of the vote according to official results, had not been widely considered the leading candidate. Long in the shadow of his father, the late opposition leader Etienne, he startled Congo last year by breaking away from the opposition’s unity candidate, Fayulu, to stand on his own.

Fayulu, a former Exxon manager and Kinshasa lawmaker, received 34 percent of the vote in the official results. He was a vocal activist during the two-year delay in Congo’s election, insisting it was time for Kabila to go. Fayulu was backed by two popular opposition leaders barred by the government from running.

Even before the election announcement, some observers suggested that Kabila’s government might make a deal with Tshisekedi as hopes faded for ruling party candidate Emmanuel Ramazani Shadary, who received just 23 percent of the vote.

Many Congolese objected to Shadary, suspecting that Kabila would continue to rule from behind the scenes.

France’s foreign minister bluntly cast doubt on the official results. Belgium’s foreign minister said his country planned to raise election concerns at the U.N. Security Council.

The delayed results, 10 days after the Dec. 30 vote, came after international pressure to announce an outcome that reflected the will of the people, with the United States threatening sanctions.

The largely peaceful election was marred by the malfunctioning of many voting machines that Congo used for the first time. Dozens of polling centers opened hours late as materials went missing. In a last-minute decision, some 1 million of the country’s 40 million voters were barred from participating, with the electoral commission blaming a deadly Ebola virus outbreak.

Defiantly, tens of thousands of voters held their own unofficial ballot on election day, and Fayulu won easily. That community, Beni, was calm on Thursday.

Congo’s government cut internet service the day after the vote to prevent speculation on social media. It remained off in parts of the country on Thursday.

Some Congolese weary of Kabila’s 18-year rule, two turbulent years of election delays and years of conflict that killed millions of people said they simply wanted peace. Some said they would be happy as long as Fayulu or Tshisekedi won, recalling the violence that followed past disputed elections.

Kabila has ruled since 2001 in the troubled nation rich in the minerals key to smartphones around the world and has amassed vast wealth. He is barred from serving three consecutive terms, but until he announced last year that he would step aside many Congolese feared he’d find a way to stay in office.

Now Congo faces a new leader who is little known after spending many years in Belgium and standing behind his outspoken father. The 56-year-old Tshisekedi took over as head of Congo’s most prominent opposition party in early 2018, a year after his father’s death.

Gleeful Tshisekedi supporters in Kinshasa, a lively opposition stronghold, said they were delighted by the win and happy to see Kabila step down.

“This is the coronation of a lifetime,” said the deputy secretary-general of Tshisekedi’s party, Rubens Mikindo. “This is the beginning of national reconciliation.”

Associated Press journalists Saleh Mwanamilongo and David Keyton in Kinshasa and Angela Charlton in Paris contributed.