FILE PHOTO: Burundi's President Pierre Nkurunziza

Burundian President Pierre Nkurunziza said in a surprise announcement on Thursday that he will not run in the 2020 elections, despite a recent referendum allowing longer term limits.

"Our presidential mandate will end in 2020," said Nkurunziza, who has been in power since 2005, at a ceremony in central Gitega province.

"I am ready, with all my heart and all my intelligence, to support the one who will be the new president in 2020," added the 54-year-old former rebel leader who was recently declared "supreme eternal leader" by the ruling party.

Nkurunziza made the announcement some two weeks after a large majority of Burundians voted "yes" in a referendum on presidential term limits that could allow Nkurunziza to stay in power until 2034.

The East African nation's constitution previously allowed leaders to serve two five-year terms.

Based on the referendum, the constitution has been amended so that Nkurunziza could serve another two seven-year terms when his current term runs out in 2020, meaning he could stay in power until 2034.

Many people in Burundi believed the referendum had been orchestrated by the ruling party to ensure Nkurunziza's grip on power.