Burundi’s President Pierre Nkurunziza, aged 55, has died after suffering a cardiac arrest, the government says.
He was admitted to hospital on Saturday after feeling unwell, his condition improved but on Monday he had a cardiac arrest and efforts to revive him were unsuccessful, officials say.
After 15 years in power, Mr Nkurunziza was due to step down in August.
In 2015, the announcement that he would run for a third term plunged the country into chaos.
It sparked anger as some questioned the legality of a third-term bid.
There was a failed coup attempt, hundreds of people died in clashes and tens of thousands fled the country.
After a change in the constitution, he was able to run for a further term in last month’s election but he decided to retire and was to be known as the “supreme guide to patriotism”.
He was also due to receive a $540,000 (£440,000) retirement pay-out and a luxury villa.
Since last week, Mr Nkurunziza’s wife, Denise Nkurunziza, has been receiving medical treatment in Kenya.
She was rumoured to have tested positive for coronavirus – a disease Mr Nkurunziza had appeared to downplay, holding an election in the midst of the outbreak, and even expelling World Health Organization representatives from the country.
The government has announced seven days of national mourning.
According to the constitution, if the head of state dies in office then the president of the national assembly, currently Pascal Nyabenda, should succeed him.
The winner of May’s presidential election, Evariste Ndayishimiye, is due to be sworn in as president in August.