Protestants in the Democratic Republic of Congo have joined Catholic calls for the country's electoral commission to release the results of the bitterly contested election.

The presidential election was held after President Joseph Kabila stepped down in what would be the first democratic transfer of power since DRC's independence. However, it has been marred by delays in counting votes and breakdowns in voting machinery, leading to fears the result might be rigged.

In a statement, the Church of Christ in Congo (ECC) appealed to the election commission to 'uphold its promises, made before God and before the nation, to offer the nation the truth, and nothing but the truth, of the ballot box'.

The powerful Roman Catholic Church has previously said it knew who had won the election because it had monitored polling stations. It called on the electoral commission to 'publish the election results in keeping with truth and justice'.

Riot police were deployed today at the commission headquarters in the capital, Kinshasa, amid speculation that the tally could be announced later in the day after the commission met all night and into the morning.

Police also took up positions along the city's main boulevard, as Congolese fretted about possible violence amid suspicions that the government was negotiating a power-sharing deal with one opposition candidate.

The electoral commission (CENI) announced on Tuesday evening it had initiated "a series of evaluation meetings and deliberations, at the end of which it will proceed to the publication of provisional results from the presidential election".

Some Congolese said they were gearing up for potential unrest.

'Everyone...voted against the government in place. We are preparing fully to demand victory if it is stolen from us,' said Augustin Bujiriri, a 25-year-old student in Goma.

The results were originally due last Sunday but were postponed due to delays tallying the vote. President Joseph Kabila is due to leave office this month after 18 years in power – and two years after the official end of his mandate. He backed his former interior minister, Emmanuel Ramazani Shadary, in the election.

Shadary was competing against two main opposition candidates, businessman Martin Fayulu and Felix Tshisekedi, the president of Congo's largest opposition party.

Tshisekedi's camp, which says it expects to win, said on Tuesday that it had met with Kabila's representatives to ensure a peaceful transfer of power, although Kabila's camp denied any such meetings had occurred.

Supporters of Fayulu, who had a healthy pre-election poll lead, have voiced suspicions that Kabila may be looking to negotiate a power-sharing agreement with Tshisekedi if Shadary loses.

On Tuesday, Fayulu and six other presidential candidates issued a statement saying that the results 'cannot be negotiated'.

Tshisekedi's spokesman, Vidiye Tshimanga, on Wednesday sought to play down the contacts with Kabila's representatives, saying they had occurred only on the sidelines of meetings with the CENI and regional observers about the electoral process.

Domestic election observers say they witnessed serious irregularities on election day and during vote tallying, although a regional observer mission said the election went 'relatively well'.

Additional reporting by Reuters.