Election officials have started counting votes in the Democratic Republic of Congo's (DRC) chaotic elections, while some voters were still casting their ballots in a poll tainted by disorganisation, violence and claims of fraud.
Voting continued on Tuesday as thousands of voters who had not been able to vote on Monday returned to polling stations.
Four out of the 11 presidential candidates have demanded the annulment of elections due to alleged irregularities.
Three of the candidates, who include Senate speaker Leon Kengo, issued a joint statement alleging the uncovering of "fictitious" polling stations and pre-marked ballot papers benefiting incumbent President Joseph Kabila.
They also complained about a ban on political rallies imposed on the last day of campaigning Saturday, the "use of state resources" by Kabila, the non-opening of numerous polling stations, a lack of ballot papers and the exclusion of opposition party monitors from counting stations.
The three said they attached "no credibility" to the results of Monday's vote and "demand the invalidation, pure and simple, of these elections given the breaches and irregularities".
Opposition candidate Vital Kamerhe called on Tuesday for the elections to be annulled, alleging systematic fraud.
"There can be no doubt as to the scale of the fraud, deliberately planned by those in power with the connivance of
the national election commission," said Kamerhe in an open letter.
Kamerhe is considered one of the leading candidates and was a former minister in incumbent President Joseph Kabila's government.
Monitors have reported widespread election fraud and chaos as votes were counted Tuesday after a campaign and polling day marred by deadly violence.
Al Jazeera's Yvonne Ndege, reporting from Kinshasa, said: "In some places, you had voters showing up to find that their names were not on the electoral register.
"And in other places, it was just the slowness of the vote itself," said Ndege, adding that many people were outside polling stations, waiting to vote.
Workers not paid
Mounoubai Madnodje, spokesman for the UN mission in Congo known as MONUSCO, said the UN was still delivering electoral materials on Tuesday to some areas which have yet to vote, including the central province of Bandundu.
Fraud allegations had been raised ahead of the polls
Things were calm, but electoral workers at one polling complex alleged they had not been paid for running the polls.
About 77 workers, who ran the voting process at the La Joie school, were conducting a sit-in at 18 offices and refusing to release equipment until they were paid.
"We worked from 5am on the 28th until 8am this morning - managing the process and counting all the ballots," said Landry Nkela, 24.
Meanwhile, Cyrille Mihona, a senior electoral official, told Al Jazeera that votes were still being counted across the city, though provisional results would be consolidated by the early evening.
Al Jazeera's Azad Essa said the eastern city of Goma was bustling with activity on Tuesday after a long weekend of last-minute campaigning and voting the previous day.
Security remained around polling stations as counting continued throughout the day, and police patrols on flat bed trucks could be seen intermittently around the city.
Scores perused polling stations to take a peek at the provisional results handwritten on paper bills posted on office walls and windows inside polling complexes.
The disturbances in Kinshasa and in the neighbouring province of Katanga seemed to have little effect on daily routines on the ground in Goma, though one voter at a polling station told Al Jazeera that the troubles in Katanga "were Kabila's people trying to start a war" because of the perceived success of opposition candidate Kamerhe.
Across the nation, voters complained that confusion over voter lists made it difficult for many to know where to vote.
The election commission said the ballot was "satisfactory".
Tensions flared and violence was reported at many polling stations during voting, over allegations of fraud.
"Here in Kinshasa we don't have any confidence in the process but in this polling station we have worked hard [to stop fraud]," said Henriette Kilonda, an election official at the Ecole de la Gare voting centre in Gombe, central Kinshasa.
It was too early to ascertain any voting trends and full provisional results are not due till December 6.
The election commission did not say how many people were unable to vote on Monday or when they would do so, but a senior international election observer said the figure was in the hundreds of thousands.
In counting that lasted through the night in some places, some ballot papers in the legislative vote were dozens of pages
long, so officials had to flick through them looking for a single "X" marking a vote.
"We have 63,000 polling stations. If of those we have even 1,000 which cause problems, that's manageable. For us we just want everyone to be able to vote," election commission spokesman Matthieu Mpita said on Monday evening.
Violence and intimidation
Anaclet Tshimbalanga, the president of TDH, a human rights group in West Kasai province, said at least 12 polling stations had been torched in the provincial capital, Kananga, after residents said they had found ballot papers already marked in favour of Kabila.
"I saw them, other observers saw them, journalists saw them, they exist," he stated, adding delays meant voting was continuing late into the night.
The business centre of the largely pro-Tshisekedi capital, Kinshasa, was calm in the morning.
Overnight, there was a heavy police presence on the streets and reports of gunfire coming from some neighbourhoods.
Highlighting the risk of the vote polarising the nation, Kazadi Nyembwe, a senior figure in Kabila's PPRD party, said its supporters had been intimidated in opposition strongholds, especially the Kasai provinces.
"Things have not gone properly. PPRD supporters weren't even allowed to go into (polling stations) unless they agreed to voted for Tshisekedi," he told Reuters late on Sunday.
Congo's first post-war election was held in 2006, drawing a line under years of war and chaos and paving the way for renewed investor interest in a country rich in copper, cobalt, gold and other minerals.
That vote was largely seen as free and fair.
Al Jazeera's Azad Essa contributed reporting from Goma in the Democratic Republic of Congo. Follow him on Twitter for the latest updates: @azadessa