Outside, a statue of his father, Laurent-Désiré Kabila, a former rebel fighter turned authoritarian leader, rises in front of the sprawling complex, an index finger pointing at the sky as if he were about to sound a warning. Just a few days earlier, at least three people were killed in clashes with the police on the sidelines of an opposition rally, and a fire broke out in a building in the capital, where voting materials are kept. Around 8,000 of the 10,000 machines expected to be used for the city were destroyed, officials said, adding that the voting would go ahead anyway.

Earlier, Mr. Kabila had appeared suddenly in front of reporters, having kept them waiting for hours in a stifling hallway in the presidential palace. He sported a white-tinged beard and was a plumper, older, slightly more tired version of the broad-shouldered, clean-shaven man whose portrait hangs virtually everywhere here, from hotels to supermarkets. (“Do I have to lose a little weight?” he asked, patting his stomach.)

Over the summer, Mr. Kabila stunned the nation by naming as his favored successor Emmanuel Ramazani Shadary, a former interior minister whose name resonates little beyond political circles in this country two-thirds the size of Western Europe. Mr. Shadary, considered to be a hard-liner, was said to have been chosen because he is malleable and has weak ties to the army and security services, two forces deeply loyal to Mr. Kabila.

Mr. Shadary, who was targeted by a fresh round of sanctions by the European Union last week for brutally repressing protesters last year, is one of 21 candidates seeking the presidency and a whopping 30,000 candidates scrambling for presidential, legislative and provincial seats throughout the nation.

According to a recent poll conducted by the Congo Research Group at New York University, Mr. Shadary trails the two leading opposition candidates. But he is expected to win, nevertheless.

The opposition has been severely weakened and divided by the defection of two prominent candidates who broke ranks to form their own ticket.