Bishops have accused authorities of violently persecuting opponents, as the government continues to reject repeated claims of human rights abuses. Since 2015, at least 1,200 people have been killed in political clashes.
The Catholic Church has denounced political violence and intolerance in Burundi in the lead-up to next year's elections. The church joins a growing number of human rights groups and organizations who are increasingly critical of the government.
In a letter read out in churches on Sunday, the Conference of Catholic Bishops of Burundi expressed concern over efforts to "suffocate and assault certain political parties and to persecute their members."
"Criminal acts go as far as murders with political motives ... perpetuated against those with different opinions of the government," the letter read.
Burundi is due to hold an election on May 20 next year, five years after President Pierre Nkurunziza's bid for a third term in office sparked a wave of unrest across the country.
Bishop Bonaventure Nahimana, a senior leader in the Burundian Catholic Church, said the government is hampering the democratic process.
"In many provinces, there are plans in place to harass and bully some political parties and their members," he said. "On top of that, there is [evidence] of behavior that is jeopardizing the electoral process."
Burundian authorities responded strongly by accusing the bishops of "spitting venomous hatred," with the secretary general of the ruling CNDD-FDD, Evariste Ndayishimiye, accusing the church of "sowing division."
Presidential spokesman Willy Nyamitwe also took to Twitter, suggesting "some bishops should be defrocked."
Relations between Nkurunziza -- a devout evangelical -- and the Catholic Church have been tense ever since the church opposed the president's bid for the third term in 2015, claiming it was a breach of the constitution.
Rights groups defend bishops' stance
Human rights groups have defended the bishop's actions, saying the statement echoes ongoing reports about the politicization of violence in the country.
"We are absolutely not thinking that this is a controversial statement by the Catholic Church," Lewis Mudge, the Central Africa Director at Human Rights Watch (HRW) told DW. "On the contrary, this statement matches what independent analysts and what independent investigators have been concluding for the last several months."
The Burundian government has been highly critical of reports issued by human rights groups and international organizations. In March, Burundian authorities forced the United Nations (UN) to shut its human rights office in Bujumbura after 23 years, branding their investigations into crimes against humanity as "lies."
"Ironically, the government is telling the Church to stay in its place, while at the same time it eliminates any meaningful attempt by any other actor to actually do any type of investigation into the multitude of human rights abuses that occur in the country," said Mudge.
A Burundian journalist who wishes to remain anonymous told DW that despite the Burundian government's harsh response, groups such as the Catholic Church were unlikely to shy away from speaking out when ordinary citizens can't.
"The Catholic Church, whose followers in Burundi are estimated at more than 70% will never fear to denounce the government's malpractices," he said.
'People are now too afraid'
Since 2015 at least 1,200 people have been killed in clashes with security forces and more than 400,000 have fled the country. Earlier this month a team of UN investigators -- now conducting their research from outside the country -- warned of heightened tensions ahead of the elections.
"People are now too afraid to speak about what they see, or family members who have been killed," says Mudge. "There is a climate of fear that permeates across the country because people have been told they will be punished if they speak with independent investigative bodies."
In particular, the ruling party's much-feared youth league, the Imbonerakure, has been accused of taking the place of security forces and carrying out killings, kidnappings, arbitrary arrests and acts of torture and rape against actual or perceived political opponents. HRW has described the violence against real or perceived opponents as a "concerted campaign."
Since the Ministry of Home Affairs approved the new political party, the National Congress for Liberty, in February, its offices across the country have repeatedly been vandalized since March, members say.
Will 'God-ordained' president stand down?
Nkurunziza has announced he will not stand for election in 2020, confusing those who have accused him of trying to maintain his grip on power.
But Mudge says he is not optimistic the president will step down as promised.
"This is an individual who has declared he has been ordained by God to rule over Burundi," he told DW. "I think he is following in the footsteps of other regional leaders, such as Paul Kagame of Rwanda, or Yoweri Museveni of Uganda, in announcing that they won't run again and then just changing their minds later down the line."
But whatever Nkurunziza's decision, it is unlikely to resolve the core issues in Burundi.
"The CNDD-FDD ruling party continues to extract a heavy toll on anyone who doesn't abide by their standards and the rules," said Mudge. "This is beyond one individual: It extends to the ruling [party] and its absolute refusal to cede any political sphere."
After almost three years of talks led by the East African Community (EAC), the Inter-Burundi Dialogue ended in failure in June. According to the International Crisis Group, the talks broke down due to the lack of political will and the Burundian government's "intransigence." Regional leaders remain reluctant to engage with outside institutions in the mediation process, increasing the risk of serious violence in the lead-up to the 2020 elections.