TIMELINE: Guinea-Bissau's history of coups and strife

(Reuters) - Soldiers killed Guinea-Bissau's President Joao Bernardo "Nino" Vieira on Monday in an apparent revenge attack for the slaying of the army chief of the unstable West African country.

General Batista Tagme Na Wai, the chief of staff, served in a military junta that overthrew military ruler Joao Bernardo "Nino" Vieira in the 1990s and had been critical of the veteran ruler since Vieira was voted back to the presidency in 2005.

Analysts say instability has been worsened by the presence of Latin American drug gangs who use the country as a staging post for smuggling Colombian cocaine to Europe.

Following are key events in the history of the former Portuguese colony and its recent political crisis.

July 1961 - The African Party for the Independence of Guinea-Bissau and Cape Verde (PAIGC) launches a guerrilla war against Portuguese rule.

Jan 20, 1973 - PAIGC leader Amilcar Cabral is assassinated by PAIGC dissidents; PAIGC unilaterally declares Guinea-Bissau independent.

Sept 10, 1974 - The state is officially established and Cabral's brother Luis becomes president.

Nov 14, 1980 - Prime Minister Joao Bernado Vieira overthrows Cabral; military-dominated revolutionary council takes control.

July/Aug, 1994 - Multi-party presidential and legislative elections are held. Vieira wins presidential election in a runoff against Kumba Yala.

May 7, 1999 - Soldiers topple Vieira in a dispute over implementation of the transition.

Nov 28, 1999 - Presidential election held; Yala wins most first round votes, followed by PAIGC leader Malam Bacai Sanha, who briefly led transition period. Yala wins runoff in January 2000 against Sanha.

Sept 14, 2003 - Army chief of staff General Verissimo Correia Seabra declares himself interim president after the army seizes power and pledges to restore constitutional order following repeated delays to new elections. Yala formally resigns three days later.

July 28, 2005 - Former military ruler Vieira is announced winner of July 24 runoff vote against Malam Bacai Sanha of the main PAIGC. Sanha's supporters say they reject the results, although PAIGC later accepts result.

Nov 2 - President Vieira names close ally, Aristides Gomes, as prime minister after sacking the administration of his political rival Carlos Gomes Junior on October 28.

March 29, 2007 - Aristides Gomes resigns as prime minister after three main parties, PAIGC, Social Renewal Party (PRS) and the United Social Democratic Party (PUSD), sign up to a "stability pact" and carry a no-confidence vote against him.

Feb 29, 2008 - PAIGC withdraws support for Prime Minister Martinho Ndafa Kabi, breaking year-old stability pact.

July 27, 2008 - Opposition PAIGC announces it is pulling out of national unity government after its representatives are sacked from senior financial posts.

Aug 6 - Rear-Admiral Jose Americo Bubo Na Tchuto, the head of the Navy, is suspended and put under house arrest.

Aug 8 - Army says military officers tried to stage coup a week earlier. Na Tchuto and other officers being questioned.

Nov 23 - Vieira survives attacks by dissident soldiers armed with machineguns and rocket-propelled grenades. As a result Interior Ministry recruits a 400-strong presidential bodyguard.

Jan 4, 2009 - One or more members of the militia shoot in vicinity of Armed Forces Chief of Staff Na Wai, although nobody is injured. Armed Forces Command says Na Wai was deliberately targeted and orders presidential bodyguard to be disbanded. Members of the bodyguard say the shooting was unintentional.

March 1 - Na Wai killed in attack on armed forces headquarters.

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