A Burundian opposition politician arrested over unrest triggered by President Pierre Nkurunziza's decision to run for a third term says he has been released.

Audifax Ndabitoreye was arrested after a meeting between East African Community foreign ministers seeking to end the crisis and Burundi leaders at a hotel in the capital, Bujumbura.

Ndabitoreye said late Wednesday, hours after the arrest, that he is free but the police may ask him to report back. Police had said Ndabitoreye, a presidential candidate, is suspected of insurrection.

Protests have rocked Burundi's capital since the ruling party announced on April 25 that it had nominated Nkurunziza as its presidential candidate.

At least nine people have been killed in the protests and more than 20,000 Burundians have fled to Rwanda, fearing political violence