The incumbent won a vast majority of the votes, but opposition candidates called it a sham and wanted supporters to protest.
Democratic Republic of Congo's President Felix Tshisekedi was re-elected for a second term on Sunday, but the opposition has demanded a re-run of the election they condemned as a "sham."
According to the country's election commission, CENI, Tshisekedi received 73% of the vote, giving him a commanding lead over his 18 challengers.
The turnout of the election on 20 December was estimated to be over 43% of the country's eligible 18 million voters.
Opposition rejects 'sham' election
The election was marred by widespread logistical problems, with many polling stations opening late or not opening at all. Some lacked materials, and many voter cards had smudged ink that made them illegible.
In some parts of the country, voting had to be extended into a second day.
Opposition leader Moise Katumbi, who garnered 18% of the ballots cast, and eight other opposition candidates signed a declaration on Sunday rejecting the results and calling for a re-run.
"We categorically reject the sham election ...and its results," the main opposition candidates said in a joint declaration. "We call on our people to take to the streets en masse after the proclamation of the electoral fraud."
"It's a farce, don't accept (the results)," Martin Fayulu, who finished third said.
Congolese law allows election results to be contested by opposition candidates or their affiliates within two days.
Katumbi, however, already ruled out mounting a legal challenge to the CENI's results, citing the alleged lack of independence of state institutions.
US calls for peaceful resolution
Meanwhile, the US urged for a peaceful and transparent resolution of any electoral disagreements.
"Any election disputes should be resolved peacefully and in accordance with Congolese electoral law," a US State Department spokesperson said.
"We call on the relevant authorities to ensure any complaints are handled in a fair and transparent manner."
President promises fight against inequalities
Barring in any legal issues, Tshisekedi will be sworn in for a second term on 20 January.
In and address to his supporters, Tshisekedi promised to address inequalities in his second term.
"You believed in my commitment not to spare any effort so that our country will retake its rightful place and so that the Congolese people will recover their pride and dignity in belonging to this country," he said.
"You believed in my fight against inequalities that have for a long time characterized our society," he said.