"Alexis Sinduhije is the leader of the terrorist gang responsible for attacks ... According to national and international law, these attacks constitute acts of terrorism and crimes against humanity," Nyandwi said in a statement on Wednesday, as quoted by the national Iwacu news website.
The terrorist group's leadership consists of seven more people, including MSD Secretary General Francois Nyamoya and local activist Marguerite Barankitse, the statement said, adding that international arrest warrants issued against those who are currently outside of Burundi.
The prosecutor general called on the member states of the East African Community and the International Conference on the Great Lakes Region (ICGLR) to assist the Burundi authorities to apprehend them. This is under various judicial covenants.
The opposition party has, however, refuted the claims on Thursday, slamming the authorities' accusations as groundless.
Several grenade explosions have hit the country's capital of Gitega and the largest port city of Bujumbura in recent days, with the latest of them exploding on Monday. The blasts left several people dead and over 100 others injured.