Deby’s win prolongs the rule of the family that has had a firm grip on power for decades.

Deby, who seized power the day rebels killed his father President Idriss Deby in 2021 and declared himself interim leader, got 61 percent of the vote, well ahead of second-placed candidate Succes Masra with 18.54 percent, the council said on Thursday.

The oil-producing country is the first of a string of coup-hit states in West and Central Africa’s Sahel region to attempt a return to constitutional rule by holding elections.

It has remained a key Western ally in the fight against al-Qaeda and groups linked to ISIL (ISIS) in the Sahel region, even as Niger, Mali and Burkina Faso expelled Western forces and turned to Russia for support instead.

But Washington and former colonial power France have kept a wary eye since Chad’s air force chief last month told the US to halt activities at an airbase, citing problems with paperwork. The US announced a temporary withdrawal of at least some troops in response.

Masra, who has served as prime minister of a transitional government since January, on Monday lodged an appeal with the constitutional council to challenge preliminary results released last week.

Masra claimed victory before the official announcement of preliminary results, alleging that an electoral fraud was being planned. He said he would give a live address later on Thursday.

Chad has experienced coups, authoritarian governments and rebel attacks since its independence from France in 1960.

Albert Pahimini Padacke, the other candidate who challenged the preliminary results, congratulated Deby on his win.

The constitutional council ruled that both complaints had lacked sufficient proof.

“In view of the votes cast on the occasion of the presidential election of May 6, Mahamat Idriss Deby having obtained … more than the absolute majority of votes cast, that it is appropriate to declare him president-elect of the republic,” the council’s president, Jean-Bernard Padare, said.

International rights groups had said the election would be neither credible nor fair.

The International Federation for Human Rights had warned that the election appeared “neither credible, free nor democratic”.

The International Crisis Group also noted that “a number of problems in the run-up to the balloting cast doubt on its credibility.”

Deby’s victory prolongs the rule of the family that has had a firm grip on power since Deby’s father took over in a coup in the early 1990s.

At least 10 people, including children, were killed and dozens were injured by celebratory gunfire on Friday following the announcement of the preliminary results, according to Amnesty International and Chadian media.