Burundian police on Saturday night uncovered eight grenades hidden in a small bush at Sororezo in Kanyosha district in Bujumbura Rural province, 10 kilometers southeast of the Burundian capital Bujumbura, the police spokesman said.
He said the eight grenades included five defensive grenades and three offensive ones.
Burundi has faced a political crisis since April 2015 when Nkurunziza announced his controversial decision to run for a third term, which he eventually won in an election boycotted by main opposition candidates.
Since April 2015, at least 410,000 Burundians have fled to neighboring countries, including the Democratic Republic of the Congo, Rwanda, Uganda and Tanzania, the UN refugee agency said in May.
The refugee population is expected to increase by 26 percent by the end of 2017, according to the agency.