Bujumbura: Burundi, which holds presidential elections on Tuesday, has been in turmoil since April with deadly protests against President Pierre Nkurunziza`s divisive bid for a third term.
At least 100 people have been killed and scores wounded in clashes between demonstrators and police and ruling party militia. More than 150,000 people have fled to neighbouring countries.
The opposition says Nkurunziza`s move is unconstitutional and violates a peace deal that ended a civil war in 2006.
Here are the key dates and events leading up to Tuesday`s vote.
April 26, 2015: Police clash with protesters in several parts of the capital, a day after Nkurunziza is declared candidate for a third term in office by his ruling CNDD-FDD party.
Police use live rounds, tear gas and water cannon to prevent thousands of youths from marching to the city centre. Demonstrators are shot dead in clashes with police, others are killed in alleged attacks by the ruling party`s youth wing, which have been likened to a militia.
May 5: The Constitutional Court clears Nkurunziza to run for a third term. The judgement, signed by six out of seven judges, comes hours after the court`s vice-president fled the country after refusing to sign the judgement, claiming judges had been subjected to death threats.
May 9: The government orders protesters to "immediately and unconditionally" end the protests and orders all barricades to be removed within 48 hours. Demands are ignored.
May 13: A top Burundian general, Godefroid Niyombare, announces the overthrow of Nkurunziza, hours after the president left for neighbouring Tanzania for talks with regional leaders on ending the crisis.
May 15: Coup leaders announce that they are surrendering after failing to capture the state broadcaster from the presidential guard. Niyombare avoids capture and goes on the run, according to the government. Nkurunziza returns to the presidential palace in the capital.
May 23: The leader of a small opposition party, Zedi Feruzi, is shot dead.
June 28: Parliament head Pie Ntavyohanyuma announces he has fled to Belgium, denouncing the president`s "illegal" third term bid.
June 29: The ruling CNDD sweeps to an expected overwhelming victory in parliament elections that were boycotted by the opposition and criticised by the international community.
July 1: Six people, including one police officer, are killed in gun battles in Bujumbura`s Cibitoke district. Five of those killed were members of an armed group, police said.
July 6: East African leaders demand Burundi delay the presidential election by two weeks until July 30. It is only delayed by one week to July 21.
July 10: Clashes between the army and gunmen in the provinces of Kayanza and Cibitoke, near the border with Rwanda and Democratic Republic of Congo. More than 220 people are captured, according to the army.
July 15: Rival political factions meet for crisis talks mediated by Ugandan President Yoweri Museveni, a last-ditch effort following months of violence ahead of the presidential polls. Museveni`s defence minister later stands in for him.
July 19: The talks are suspended amid mutual recriminations, after the government fails to show up.
July 20: At least two people killed in night clashes in Bujumbura, with explosions and gunfire reported.
July 21: Polls open at 6:00 am (0400 GMT), with shooting and explosions in Bujumbura. Voting due to close at 4:00 pm (1300 GMT).
