Democratic Republic of Congo's ruling coalition accused the country's Catholic Church on Friday of behaving in an "irresponsible and anarchic" way after it said it knew the winner of last Sunday's presidential election. The Church's bishops' conference, known as CENCO, said on Thursday its vote tallies showed a clear victor in the Dec. 30 poll, a pronouncement widely seen as a warning to authorities against rigging the vote. The coalition "firmly deplores...the partisan, irresponsible and anarchic attitude of CENCO," said Barnabe Kikaya Bin Karubi, an adviser to outgoing President Joseph Kabila and a spokesman for Kabila's hand-picked candidate, Emmanuel Ramazani Shadary. "This seriously violates not only the constitution but also the electoral law." The retort sets up a standoff between the government and the Catholic Church, one of Congo's most powerful institutions which represents about 40 percent of its 80 million people. It further stokes tensions after a chaotic election that observers and the opposition say was marred by serious irregularities. The opposition, represented by its two main candidates Martin Fayulu and Felix Tshisekedi, and Shadary's camp have all claimed they are on course to win, without posting specific figures. Kikaya later told Reuters Kabila had met Catholic bishops on Friday but provided no details. The government says the election was fair and went smoothly. The electoral commission (CENI) is scheduled to announce results on Sunday but it has said that there could be delays because of the slow arrival of tally sheets. The poll is meant to lead to Congo's first democratic transfer of power, but the international community has raised concerns that a disputed result could spark unrest, as was the case after the 2006 and 2011 elections. The United States called on CENI on Thursday to publish accurate results and threatened sanctions against anyone who sought to undermine the process. An election dispute could further destabilise Congo's volatile eastern provinces, where wars around the turn of the century resulted in millions of deaths, most from hunger and disease, and where dozens of militia remain active. Kabila's government cut access to the internet as well as Radio France Internationale (RFI) and some local media this week, saying it wanted to prevent fake results from circulating. The United Nations' human rights office warned on Friday that the move could cause a violent backlash when results are announced. "This being a very sensitive, a very tense period, we are concerned that these efforts to silence dissent could backfire considerably when the results are announced," Ravina Shamdasani, spokeswoman for the U.N. High Commissioner for Human Rights, told reporters in Geneva. "We are watching carefully and we are calling on all sides to refrain from the use of violence," she said. Pre-election opinion polls showed Shadary trailing Fayulu and Tshisekedi, who have been buoyed by rising dissatisfaction with Kabila's tenure. Kabila, who succeeded his assassinated father in 2001, helped reunify the country amid civil war and has presided over strong economic growth, driven by exports of copper and cobalt, a component of electric car batteries. But critics say there has been little improvement in the quality of life for average Congolese and accuse the government of brutally suppressing dissent.