Leader of one of the Burundian opposition parties was shot and killed alongside his bodyguard in capital Bujumbura late on Saturday.
Zedi Feruzi, the head of the Union for Peace and Democracy Party (UPD), was killed outside his home in Ngagara district of the capital when gunmen approached him with a car and opened fire.
Feruzi, a member of Muslim minority in Burundi, was a well-known figure although his party was not among the nation's biggest.
Assailants could not have been identified so far.
The incident came following weeks of violence and a failed coup attempt in the country as the tension remains high with President Pierre Nkurunziza pushing a run for a third term in office, which opposition claims to be unconstitutional.
Feruzi had spoken against Nkurunziza in the past and some opposition figures and observers blamed his death on the president.
Burundi has been plagued with violence April, after the ruling National Council for the Defence of Democracy named incumbent President Pierre Nkurunziza as its candidate for June presidential elections.
The Burundian constitution limits the presidency to two terms in office, but Nkurunziza's supporters say he can run again because he was elected by the parliament, not the people, in his first presidential term, a claim backed by country’s constitutional court.
Since the beginning of the protest, 26 have been reportedly killed, hundreds injured and more than 100,000 had to flee the country.