Ivory Coast prime minister and presidential candidate Gon Coulibaly died after falling ill at a cabinet meeting in the presidential palace on Wednesday.
Gon Coulibal, 61, had returned from France where he had been receiving treatment for a heart condition. He became unwell at a weekly cabinet meeting and was taken to hospital where he later passed away.
President Alassane Ouattara said the country was in mourning and paid tribute to his “closest collaborator” in a statement published on Wednesday.
“I salute the memory of a statesman, of great loyalty, dedication and of love for the fatherland,” he added.
Couilabl, who received a heart transplant in 2012, had been chosen as the ruling party’s candidate for the upcoming presidential election in October, after Mr Ouattara confirmed he would not seek a third term in office.
His death is likely to set off a scramble for power within the ruling Rally of Houphouetists for Democracy and Peace (RHDP) party.
There is no clear-cut replacement for him in an election widely considered a test of stability for the world’s top cocoa producer.
Defence minister Hamed Bakayoko had served as interim prime minister while Gon Coulibaly was in France for two months for tests and rest.
Ouattara had designated Gon Coulibaly as the RHDP candidate in March after announcing that he himself would not seek a third term.
“It’s really a shame. He was well on his way to leading Ivory Coast as president,” said Bertin Malan, a resident in Abidjan’s Yopougon neighbourhood.
Derided by critics as uncharismatic, Gon Coulibaly rode Ouattara’s coattails to the heights of Ivorian politics.
Gon Coulibaly served as secretary-general of the presidency from 2012-17 before being appointed prime minister.
He had also served as agriculture minister under Ouattara’s predecessor, Laurent Gbagbo.
Additional reporting by Reuters