Cyclists and others clinging to the back of a truck outside Bujumbura, capital of Burundi, where a presidential election kicks off today.

Each day, scores of cyclists make the 45km downhill journey at breakneck speed to Bujumbura from the town of Bugarama in western Rwanda to sell bananas, often hanging from the back of trucks for the return uphill trip.

Burundi has experienced violent clashes between protesters and security forces since April, following the announcement that President Pierre Nkurunziza, 51, would stand for a third consecutive five-year term - a move that his opponents say violates both the Constitution and a peace deal that ended Burundi's civil war in 2006.

The unrest in Burundi has the potential to destabilise the Great Lakes region that includes the Democratic Republic of Congo, Africa's top copper and tin producer, and Rwanda, whose economy is still recovering from the 1994 genocide.

More than 100,000 people have fled Burundi to neighbouring countries in the past three months. Civil wars in the early 1990s in Burundi and Rwanda helped lay the ground for conflict in neighbouring Congo, the deadliest war in the continent's modern history.

Burundi has a US$2.7 billion (S$3.7 billion) economy and is home to 10.2 million people. It is the continent's seventh-biggest coffee exporter and buyers of its beans include Starbucks.

REUTERS, BLOOMBERG, AGENCE FRANCE-PRESSE