- Opposition leader was assassinated Saturday
- President has postponed elections by 10 days
The country is plunging deeper into crisis following the decision of President Pierre Nkurunzinza to seek a third term in office and a failed coup earlier this month.
Domitien Ndayizeye, a former Burundian president and the head of National Gathering for Change, known as RANAC, confirmed to CNN on Sunday that opposition parties have suspended their dialogue with Nkurunzinza's government.
Pacifique Nininahazwe, a leading activist, said, "We cannot continue to talk with the threats and killings."
String of violence
Feruzi, the leader of the Union for Peace and Development party, was killed on Saturday along with his bodyguard in a drive-by shooting in Bujumbura.
A day earlier, at least three people were killed and 21 were wounded by two grenades thrown in a market attack in Bujumbura.
And last week, the president, under pressure from international bodies after violent protests, moved the election to June 6 -- 10 days later than originally scheduled.