At least three people have been killed in Burundi in a fresh outbreak of clashes between police and protesters demonstrating against President Pierre Nkurunziza's bid for a third term, Al Jazeera correspondent said.

The latest casualties bring to seven the number of people killed in unrest that began when the ruling CNDD-FDD named Nkurunziza as its candidate for the June 26 elections, according to the red Cross. 

Al Jazeera's Malcolm Webb, reporting from the capital Bujumbura, said a grenade was thrown at protesters in the Cibitoke suburb of the city, killing two protesters. 

"Protesters say it was thrown by a man in civilian clothes who they believe to be a member of the ruling party's youth wing, known as Imbonerakure," he said.

"Separately, protesters also burnt a man to death, who they said was Imbonerakure."

Red Cross's Alexis Manirakiza, speaking to Al Jazeera from Bujumbura, said they had recorded 212 people wounded since April 26 when the clashes began.

Tensions remained high in the area on Thursday with protesters arming themselves with sticks and batons.

Critics strongly oppose Nkurunziza's bid saying it is unconstitutional and violates the hard-won Arusha accord gains which ended the country's 13-year civil war based on enthnic lines.

But the president's supporters maintain that Nkurunziza, who became president in 2005, was installed by the parliament as opposed to being elected directly by people, making him eligible for another term. 

The constitutional court's only two remaining judges - five fled to neighbouring Rwanda amid pressure and threats - ruled on Tuesday that Nkurunziza's bid was valid. 

Nkurunziza announced that if re-elected he would step down after a third term. 

"I wish to inform the national and international community that if re-elected this will be the final term as provided in the ruling of the constitutional court," the president said during his address to the nation.

Opposition leaders meet

Meanwhile, East Africa foreign ministers met with Burundi's opposition in Bujumbura in the hope of striking a peace deal.

Agathon Rwasa,  leader of the National Liberation Forces (Forces pour la Libération Nationale, FNL) the main opposition party, told Al Jazeera that President Nkurunziza and his parliament were manipulating some institutions to rule in their favour.

"Whatever he said yesterday, it is a lie. He can't keep his promises and words. The fact is that he violated the Arusha agreement that brought peace to the country and you think he will keep his words now," he said.

Source: Al Jazeera and agencies