The Burundi presidency has confirmed that incumbent President Pierre Nkurunziza has been sworn in for his third term Thursday, in a surprise ceremony six days before the scheduled inauguration day.
Nkurunziza's third term bid was condemned as unconstitutional by Burundi's opposition and provoked months of protests. In mid-May, rebel generals attempted a coup, which failed.
The United Nations Electoral Observation Mission in Burundi said the vote last month was not "inclusive free and credible" and was held "in an environment of profound mistrust" between political rivals.
Nkurunziza is to take the oath of office, presidential communications chief Willy Nyamitwe said, in a surprise ceremony ahead of an August 26 deadline, when his previous mandate ends.
Nkurunziza won 69.41 per cent of the vote in the presidential elections, an immediate first round victory.
Burundi's constitution only allows a president to be elected twice - for a total of 10 years in power - but before these polls Nkurunziza argued he could run again because had only been directly elected by the public once and for his first term was appointed by lawmakers.
He has been in power since 2005 when he was elected by a parliamentary vote and was re-elected in 2010.
The 51-year-old former sports teacher and born-again Christian was a Hutu rebel leader during Burundi's 13 year-long civil war, in which at least 300,000 people were killed.
Top international envoys from the United Nations, African Union, European Union, Belgium and United States have called on all sides to "recommit to a transparent, inclusive, and comprehensive political dialogue."
AU chief Nkosazana Dlamini-Zuma on Sunday called for "utmost restraint" by all sides, warning of potential "catastrophic consequences" for troubled Burundi and the wider region if rivals do not resolve political differences peacefully.