The internet has been shut down in key cities in the Democratic Republic of Congo a day after the much-delayed presidential election.
Opposition candidate Martin Fayulu's campaign team accused the government of ordering the shut down to avoid broadcasting their candidate's "overwhelming victory".
Telecoms minister Emery Okundji said he was unaware of the situation.
Observers have complained of widespread irregularities during the poll.
Counting is underway for the vote, but provisional results are not expected until 6 January.
The current President, Joseph Kabila, is stepping down after 17 years in office. He has promised DR Congo's first orderly transfer of power since it gained independence from Belgium in 1960.
Kabila is backing his former interior minister Emmanuel Ramazani Shadary, who is the ruling's party's candidate.
The two main opposition candidates are Martin Fayulu, a former oil executive, and Felix Tshisekedi, the son of the late veteran opposition leader Etienne Tshisekedi.
In the capital Kinshasa, the internet has not been working since the morning while it is also down in the key eastern cities of Goma and Lubumbashi.
Internet provider Global said in text messages to customers that the government had ordered the shutdown, AFP reports.
The agency said a representative from the Vodacom mobile phone network also said that the government ordered them to shut the internet down.
But Telecoms Minister Emery Okundji told the BBC he was unaware of the situation.
Observers from the Catholic Church reported more than 100 cases of election monitors being denied access to polling stations.
It added that around 20 per cent of polling stations opened late, and there were reports of polling stations being moved at the last minute.
Local observers Symocel say some of their 20,000 agents were subjected to intimidation and also complained many of those casting their could not do so in secret.
n a BBC interview Mr Fayulu accused the military of "pushing" voters in some areas to cast their ballots for Mr Shadary.
Tshisekedi accused Kabila's government of creating a "mess" on election day in order to trigger legal challenges that would help the president remain in power.
President Kabila has insisted the election was free and fair.
Kabila took over from his assassinated father Laurent in 2001, but he was barred from running for another term under the constitution.
He was supposed to step down two years ago, but the election was postponed after the electoral commission said it needed more time to register voters.
The decision triggered violent clashes, as the opposition accused Mr Kabila of trying to cling on to power.
The run-up to the poll was also hit by controversy over the exclusion of some 1.26 million out of an electorate of nearly 40 million from voting.
The electoral commission said voting could not take place in the eastern cities of Beni and Butembo because of a deadly Ebola outbreak in the region. Voting was also called off in the western city of Yumbi because of insecurity there.