Burundi began an official mourning for President Pierre Nkurunziza on June 10 a day after the announcement of his sudden death from a heart attack aged 55, leaving in shock the East African nation he had ruled with an iron grip for last 15 years.

Kenyan President Uhuru Kenyatta and Ethiopian Prime Minister Abiy Ahmed were among the first world leaders to express their condolences June 9 evening, with Kenyatta hailing Nkurunziza’s “contribution to the integration and progress of the region”.

Nkurunziza, 55, started to feel unwell after attending a volleyball match on June 6, and appeared to be improving until his condition suddenly deteriorated on June 8 and his heart stopped, the presidency announced in a statement.

“Despite intense efforts, the medical team was not able to save the patient,” said the statement, adding that doctors had spent several hours trying to revive him. A post on the government’s official Twitter account early Tuesday evening announced Nkurunziza‘s death “with great sadness“, and a statement from the presidency said he died in a hospital in the eastern city of Karuzi.

Nkurunziza’s wife, Denise Bucumi Nkurunziza, has been transported to Kenya for Covid-19, Turkey’s state-run Anadolu Agency reported.