The United States, other Western nations and regional African countries had pushed Nkurunziza, 51, not to seek a third term. Washington said it was disappointed he was doing so and warned it would take steps against those behind any violence.
“In such a situation, the Burundi government asks you to observe diplomatic neutrality,” the first deputy president, Prosper Bazombanza, told a meeting with ambassadors from the United States, Europe and African nations to discuss the crisis.
Bazombanza said the protesters wanted to disrupt a series of elections which start in May with local council and parliamentary polls, followed by a presidential vote on June 26.
The unrest in the east African country raises tensions in a region with a history of ethnic conflict, and has driven almost 25,000 Burundians across the border for fear of ethnic killings.
Other presidents in the region are also nearing the end of their final terms, as defined by their constitutions. The leader of Burkina Faso in west Africa was overthrown last year after trying to change the basic law to extend his 27-year rule.
Foreign Minister Laurent Kavakure said some protest organisers were winning “a lot of sympathy” from some of Burundi’s partners, although he did not name them.
“The protests are illegal,” the minister told the ambassadors. “They are becoming an insurrection movement.”
SENDING A WARNING
Unrest has spread to new parts of the capital Bujumbura, and small protests were reported by local media in the second biggest city, Gitega.
“We have already warned the authorities that they would be responsible for any impact of the decision on security in the electoral process,” said a western diplomatic source inside the talks.
The source said the government was told that the unrest was caused by the president’s decision to seek a third term, and that it need to free up political space.
Both Washington and the European Union have indicated that any individuals who stoke violence could face sanctions.
Crowds gathered from early morning in a south Bujumbura suburb mostly inhabited by members of Burundi’s ethnic Tutsi minority, waving placards and chanting slogans accusing the president of breaking the constitution. Some burned tyres.
Opponents of the president, who led one of the militias of the ethnic Hutu majority in the civil war, say the peace deal and the constitution limit him to two five-year terms.
Supporters of Nkurunziza, whose power base is in the countryside, say his first term does not count because he was picked by lawmakers, not elected.
One protester told Reuters two people suffered gunshot wounds in the northern Cibitoke suburb, though there was no immediate confirmation from the police.
Two protesters have been killed and more than 250 people arrested since protests erupted on Sunday, Burundi’s police chief André Ndayambaje said earlier. Activists say at least five protesters have died.
The United Nations said Secretary-General Ban Ki-moon has sent his special envoy for the Great Lakes region to Burundi for talks with Nkurunziza and the opposition.
Opposition leader and presidential hopeful Agathon Rwasa told a news conference: “I am calling upon President Nkurunziza to abandon seeking another third term to prevent the country from massive violence and killings.”
Burundi’s civil war pitted the army, then dominated by the Tutsi minority, against rebel groups mostly made up of majority Hutus. The army now includes both ethnic groups.