Outgoing Democratic Republic of Congo President Joseph Kabila’s ruling coalition won a majority in legislative elections, a coalition official said on Saturday, despite opposition leader Felix Tshisekedi’s win in the presidential vote the same day.

The result will undercut Tshisekedi’s ability to deliver on campaign promises to make a break with the 18-year Kabila era and fuel suspicion that his victory, announced on Thursday, came through a backroom deal that will preserve Kabila’s influence over important ministries and the security forces.

Kabila is due to step down in the coming days in what was meant to be Congo’s first democratic transfer of power in 59 years of independence. But he has signaled he intends to remain involved in politics and might run for president in 2023 when term limits no longer apply.

The runner-up in the presidential election, Martin Fayulu, filed a fraud complaint on Saturday with Congo’s highest court to challenge the result, a campaign spokeswoman, Eve Bazaiba, told Reuters.

Fayulu says he won in a landslide in the Dec. 30 ballot with more than 60 percent of votes and accuses Tshisekedi of striking a deal with Kabila to be declared the winner.

Tshisekedi’s camp denies that there was any deal with Kabila and says meetings it held with the president’s representatives after the election were meant solely to ensure a peaceful transfer of power.

The disputed outcome threatens to reawaken violence in the huge and tumultuous central African