The ex-president of Haiti, Rene Preval, died on Friday (3 March) at the age of 74. The cause of his death is not yet known.

Preval reportedly died after falling unconscious at his home. His sister Marie-Claude Calvin said only an autopsy could reveal the cause of his death.

"He did not tell me that he felt anything was wrong with his health. It could be a cardiovascular accident but we cannot know for sure what the cause is," Calvin said.

She added that when he talked to him on Friday, "he sounded fine", but when he collapsed it became impossible for the medics at a nearby clinic to save his life.

"It was too late, he died. All that happened very quickly," Calvin was quoted as saying by Reuters.

Several Haitians have paid tribute to the deceased president, including President Jovenel Moise. "I bow low before the remains of this worthy son of Haiti," Moise tweeted in remembrance of Preval.

The US has also extended condolences, saying Preval had "shepherded his country through tragic times and good times". Preval was the only democratically-elected president of the Caribbean nation to serve two separate full terms.

Born on 17 January 1943, Preval first came into power as president in 1996 and served the nation until 2001. However, it was his second term from 14 May, 2006 to 14 May, 2011 that proved challenging for him as Haiti was hit by a powerful earthquake in January 2010, which killed around 200,000 people.

The powerful quake had also destroyed most of the parts of the capital city of Port-au-Prince, and displaced at least one million people. In a country like Haiti, which is marred by poverty and political instability, the quake was a major crisis that severely dented the economy.

Preval also served as the prime minister of the country from February 1991 to October 1991 and always remained a strong political figure in Haiti even after leaving office.