Anti-riot police with water cannon and armoured vehicles are outside the Democratic Republic of Congo's electoral commission ahead of the announcement of the first results of the presidential election.
Residents of the capital, Kinshasa, say the heavy security presence is a bad sign.
Resident John Kabamba says it "may be a message that the publication (of the results) won't meet the expectations of the Congolese people".
The first results could be announced as early as Wednesday.
DRC on December 30 voted for a successor to departing President Joseph Kabila. He backs ruling party candidate Emmanuel Ramazani Shadary, who is under European Union sanctions.
Leading opposition candidate Martin Fayulu has urged the electoral commission to announce the true results as quickly as possible and warned it not to "play with fire, it is very dangerous".