Burundi's government and opposition on Monday traded blame for grenade attacks that killed four people and wounded around 30 in ongoing violence a week ahead of key parliamentary elections.
The troubled central African nation has been in crisis since late April over President Pierre Nkurunziza's controversial bid to stand for a third consecutive five-year term, a move branded by opponents as unconstitutional and a violation of a 2006 peace deal that ended 13 years of civil war.
Many fear a repeat of that violence, which split the country along ethnic lines between the majority Hutus and minority Tutsis, as well as between rival factions within those groups.
The European Union on Monday threatened sanctions against those involved in the violence.
Presidential communications chief Willy Nyamitwe blamed the opposition for the unrest, saying they wanted a replay of the situation in 2010 when they boycotted polls.
"This terror campaign has a similarity with what happened in the aftermath of 2010," he said, blaming the attacks on "politicians and civil society activists who promised the people that there will be no elections at all in 2015."
View galleryBurundi has suffered months of political and civil …
Burundi has suffered months of political and civil unrest over President Pierre Nkurunziza's con …
Parliamentary elections are planned for June 29, ahead of the presidential vote on July 15.
The opposition rejected any involvement in violence, condemning the attacks "in the strongest terms" and accusing the government of trying to "exploit" them to get rid of their opponents.
"Our movement is and will remain peaceful," said Jeremiah Minani, spokesman of the Arusha Movement coalition, which includes opposition parties and civil society groups opposed to Nkurunziza's third term.
"We think it could be a plot to sow terror, and to blame that on his opponents in order to stop those who oppose the third term."
- 'Attacks are related' -
View galleryBurundians who fled their country, wait to be registered …
Burundians who fled their country, wait to be registered as refugees at the Nyarugusu camp in north …
Meanwhile, EU foreign ministers threatened to sanction individuals involved in Burundi's political violence.
"The EU is determined to adopt, if necessary, targeted restrictive measures against those whose actions would have led or lead to violence and repression in serious violations of human rights," it said in a statement.
The grenade blasts, which took place overnight Sunday to Monday, were the latest in a string of attacks in recent days. On Friday night, 11 police officers were wounded in a series of explosions.
The most serious attack was in the northern town of Ngozi where a grenade was hurled into a bar, killing four and wounding 25 others, 10 of them seriously, a police officer said, adding that three suspects had been arrested.
In the neighbouring northern Kirundo province, another person was wounded in a blast, while a grenade was also thrown into a bar in the northeastern Muyinga district, although no one was hurt in that attack. In Bujumbura, two policemen were wounded by a grenade on Monday morning.
"These people want to frighten the population to prevent them from voting," said Muyinga district governor, Aline Manirabarusha.
"It is clear that all these grenade attacks are related to each other, this is a terror campaign organised by opponents of the third term of President Pierre Nkurunziza, to destabilize and try to prevent the elections," a senior police officer said.
Last week, the Burundian human rights group Aprodeh said at least 70 people have been killed, 500 wounded and more than 1,000 jailed since late April, when the opposition took to the streets to protest Nkurunziza's bid to remain in power.
More than 100,000 people have fled the violence to neighbouring countries.
Nkurunziza survived a coup attempt last month and has since faced down international pressure, including aid cuts, aimed at forcing him to reconsider his attempt to stay in power.