The opposition has expressed concern that the vote could be stolen by Kabila, who had delayed elections for two years after the end of his second and final term.
CENCO deployed 40,000 observers nationwide to monitor the presidential and parliamentary polls.
CENI had wanted "to be able [to] transmit the results from the voting machines to help us publish the results quickly but nobody wanted that procedure", he said.
Each electoral area counts the vote, issues a report on the tally, and this document together with the ballots cast, is then sent to "result centralisation centres" where the results are compiled.
Meanwhile, Lamuka co-spokesperson Kamitatu said the tallies collected from almost all polling stations by Lamuka monitors clearly showed it was impossible that outgoing President Joseph Kabila's anointed successor Emmanuel Ramazani Shadary would win the election.
The Congolese election commission said logistical problems may force it to postpone publication of provisional results from Sunday's vote, which also included elections to the national parliament and provincial assemblies.
Amid rising concern, a hold-up in the return of ballots has led to a delay in announcing the victor of the Democratic Republic of Congo presidential election.
"The first of these personnel arrived in Gabon on January 2, 2019, with appropriate combat equipment and supported by military aircraft", Trump's letter to Congress read. The government has already cut internet access across the vast Central African country to prevent any speculation on social media about who might have won the election.
President Donald Trump announced on Friday that he was dispatching military personnel to African countries near Congo citing the possibility of post-election violence.
Western powers and DRC's neighbours hope sub-Saharan Africa's biggest country will see its first peaceful transition of power since independence in 1960.
Also Friday, Congo's election commission scolded the Catholic church for saying its data show a clear victor in Sunday's presidential election, asserting that the announcement could incite an "uprising".
The United States urged Congo to release accurate results and restore internet access, warning that those who undermine the democratic process could face US sanctions.
"We are waiting and trying to adapt, searching for places where we can still find network because we need it to work", businessman Paul Odimba said.
The electoral commission is slated to release provision results on Sunday, but there may be a delay because of slow vote counting.
In Washington, the State Department called on Congo's electoral commission, CENI, to ensure votes were accurately counted and threatened to impose sanctions against those who undermined the process or threatened peace and stability in the country.
That is the question observers are asking after the opposition coalition said they will not accept a result that does not declare their candidate Martin Fayulu the victor.
The DR Congo was on edge Saturday as officials delayed the announcement of preliminary results from a crucial presidential election amid growing pressure from world powers to respect voters' wishes.