Tension is high in Burundi with another explosion reported in the city center.
According to local reporters, no casualties have been recorded yet.
This comes just hours to the highly contentious presidential election.
Burundi as President Pierre Nkurunziza is all set to stand for re-election tomorrow amid opposition from his opponents who think his decision breached an agreement not to seek a third term and sparked protests in which 77 people have died.
The African Union and the U.S. have criticised Burundi for allowing the polls to go ahead.
Government forces have been attacked in the north of the country in raids the military says were carried out by suspected rebels.
More than 100,000 people have fled to neighbouring countries in the past three months.
The UN human-rights agency said last week that presidential vote is likely to cause “major instability and confrontations” that may spread across the region.
Regional leaders has appointed President Museveni to lead negotiations between the warring parties but that too has not yield much fruits as they were suspended without headway.