A spokesman for Burundi's ministry of public security says three people have died in grenade attacks during a week that has seen street protests against President Pierre Nkurunziza's decision to seek a third term.

Nkurikiye Pierre said Saturday that two police officers died in one attack on a police station in the capital's central market and a civilian died in another attack in the Kamenge area of the capital. Seventeen people were wounded in the grenade attack which occurred Friday night, said Pierre.

Pierre said police have arrested two suspects but the motive of the attacks is not known. According to the Burundi Red Cross at least six people have been killed in clashes with the police this week.