President Jovenel Moise was shot dead by unidentified attackers overnight, stirring fears of another bout of turmoil. 

Here are some key events in Haiti's political history. 

1492 - Spain colonises the island of Hispaniola after the arrival of Christopher Columbus. Two hundred years later Spain cedes the western half to France. Plantations worked by slaves of African origin produce sugar, rum and coffee that enrich France. 

1801 - Former slave Toussaint Louverture leads a successful revolt and abolishes slavery. 

1804 - Haiti becomes independent under former slave Jean-Jacques Dessalines, who is assassinated in 1806. 

1915 - United States invades Haiti, withdrawing in 1943 but keeping financial control and political influence. 

1937 - In the worst incident of long-standing rivalry with neighbouring Dominican Republic, thousands of Haitians in border area are massacred by Dominican troops on the orders of dictator Trujillo. 

1957 - Francois "Papa Doc" Duvalier takes power with military backing, ushering in a period which sees widespread human rights abuses. 

1964 - Duvalier declares himself president-for-life. His dictatorship is marked by repression, enforced by the feared Tonton Macoutes secret police. 

1971 - Duvalier dies and is succeeded by his son, Jean-Claude, or "Baby Doc". Repression increases. In the following decades, thousands of Haitian "boat people" flee by sea to Florida, many dying on the way. 

1986 – Popular revolt forces Baby Doc to flee Haiti to exile in France. Lieutenant-General Henri Namphy takes over. 

1988 - General Prosper Avril takes over from Namphy in a coup. 

1990 - Avril declares a state of siege amid protests but resigns ahead of elections under international pressure. 

1990 - Former parish priest Jean-Bertrand Aristide, a leftist champion of the poor, wins Haiti's first free election. He is ousted in a coup in 1991. 

1994 - U.S. troops intervene to oust military regime and Aristide returns. U.N. peacekeepers deploy in 1995 and Aristide protege Rene Preval is elected president. 

1999 - Aristide is elected president for a second term despite disputed results. 

2004 – Political unrest forces Aristide to flee but the country descends into violence. 

2006 – Preval wins election. 

2008 – 2010. Series of protests, triggered by food shortages, a cholera outbreak and then over elections. 

2010 – A catastrophic earthquake kills between 100,000 and 300,000 people, according to various estimates, causing widespread damage in Port-au-Prince and elsewhere. Despite an international relief effort, the country is all but overwhelmed, exacerbating political, social and economic problems. 

2011 - Michel Martelly wins second round of presidential election. 

2012-14 Frequent anti-government protests fueled by corruption and poverty. Demonstrators demand Martelly resign. 

2017 - Jovenel Moise, a banana exporter-turned-politician, is declared winner of 2016 presidential election. 

2019 - Moise steadily amasses power and rules by decree after Haiti fails to hold elections due to political gridlock and unrest. 

Thousands take to the streets chanting "No to dictatorship" and calling for Moise's resignation.