Police in Burundi have clashed with thousands of protesters angered by President Pierre Nkurunziza's decision to run for a third term in office.
The government has banned protests, deployed the army and shut down the main independent radio station, saying it was disrupting the peace.
Police have fired tear gas and water cannon, while protesters have set up barricades in the capital, Bujumbura.
At least three people were killed on Sunday as police dispersed crowds.
Mr Nkurunziza, a former rebel leader, has warned that anyone who wants to create problems for the governing party would find himself "in trouble".
Former Burundian president Pierre Buyoya, who was involved in the peace process that ended more than a decade of ethnic conflict, has warned that Burundi could return to war.
Under the constitution, presidents can only be elected to two terms in office but Mr Nkurunziza's allies say his first term does not count as he was appointed by parliament.
At the scene: Maud Jullien, BBC News, Bujumbura
In the Cibitoke neighbourhood, where some of the most violent clashes have been taking place, thousands came out to protest.
The road was black from burnt tires. Riot police and soldiers were everywhere. Protestors told us the police had been firing live rounds, and handed us a bullet case for proof. The presidency denies security forces ever used live fire.
In the same neighbourhood a young man told us his father was killed on Sunday by people he believes are pro-government militia men. If this is true, it is the type of development that many have been dreading: The involvement of armed civilians in the electoral row.
African Public Radio, known as "voice of the voiceless", is one of three radio stations whose live broadcasts have been stopped.
Police also arrested the prominent human rights activist Pierre Claver Mbonimpa.
He had previously asked the ruling party not to put the president up for a third term in June's election, arguing that it would be a violation of the constitution.
The United States has condemned the president's bid for a third term saying in a press statement that the country is "losing an historic opportunity to strengthen its democracy".
Mr Nkurunziza has been in power since 2005, when a 12-year civil war officially ended.
More than 300,000 people died in the conflict between the minority Tutsi-dominated army and mainly Hutu rebel groups, such as Mr Nkurunziza's CNDD-FDD.