Burundi's parliament failed Friday to adopt the government's highly controversial measures to revise the constitution, which could have threatened a delicate ethnic balance in a nation still healing from decades of conflict.
Lawmakers blocked the changes by a single vote, parliamentary speaker Pie Ntavyohanyuma said, adding that the "draft revision of the constitution is therefore rejected."
It also blocks the president from seeking a third term in office, likely to enrage President Pierre Nkurunziza, who was expected to campaign for a third mandate in elections scheduled for 2015.
Nkurunziza's ruling CNDD-FDD party holds the majority in parliament but the constitutional changes needed four-fifths of votes to pass, with the bid failing by just one vote.
Parliament's decision comes amid growing tensions in the central African country, with international concern about tensions between the opposition and the government.
The government had argued that its proposed changes were but a simple and minor "tweaking" of the constitution, but critics accused Bujumbura of seeking to bolster power in the ruling party.
The opposition had warned that the move risked awaking old ethnic demons which have plagued the small country, torn in the past by civil war, rebellion and massacres.
Had the changes to the constitution been approved, it would have reduced the two-thirds parliamentary majority currently needed to pass a law to a simple majority.
That would have effectively handed total legislative power to Hutu MPs who form a majority in parliament. Tutsi MPs hold 40 percent of seats in the house.
That percentage is crucial, since the constitution not only limits the stranglehold of a single political party, but also stops the Hutu majority from having political dominance over the Tutsi minority.