Nairobi - The United Nations refugee chief said Wednesday he was "extremely worried" at the political crisis in Burundi, where at over 35 000 refugees have fled ahead of elections.
"We thought Burundian refugees were something we would never have to discuss again, unfortunately we are back to having a significant outflow of Burundians," UN Refugee Agency (UNHCR) chief Antonio Guterres told reporters.
"It must stop - we have enough crises in the world."
President Pierre Nkurunziza, a former rebel leader from the Hutu majority who has been in power since 2005, has come under intense international pressure to withdraw his bid for a third term in power, which has sparked days of deadly protests.
Refugees have fled into Rwanda, Tanzania and Democratic Republic of Congo.
The United Nations last week warned that up to 400 000 people could be affected in a worse case scenario should upcoming elections in Burundi turn violent, calling for extra cash to prepare.
Burundi, where a 13-year civil war between Tutsis and Hutus ended only in 2006, has been rocked by violent protests since the CNDD-FDD designated Nkurunziza to stand in what critics say is in defiance of the constitution and the Arusha accords which ended the war.
The UN has spent millions of dollars and years of work helping Burundi refugees who fled ethnic violence and civil war to return home, but now political unrest has put the country into crisis again, he warned.
"We helped 500 000 Burundian refugees to go home in safety and dignity and we resettled 200 000 more," Guterres said in the Kenyan capital.
"We thought that was a problem that was over."