A spokesperson for Gleneagles hospital in Singapore refused to comment, citing patient confidentiality.
Zimbabwe's current leader Emmerson Mnangagwa confirmed the death on his Twitter account.
Mugabe "was an icon of liberation, a pan-Africanist who dedicated his life to the emancipation and empowerment of his people," Mnangagwa tweeted. "His contribution to the history of our nation and continent will never be forgotten. May his soul rest in eternal peace."
In early August, Mnangagwa told the country Mugabe was hospitalized abroad, but that he was on the path to recovery.
Mugabe had been regularly seeking medical treatment in Singapore during his 37 years in power and since being deposed in a 2017 coup and replaced by former deputy Mnangagwa.
The country's once-proud health care system was decimated by Mugabe's years of misrule and Zimbabwe's economic collapse. As a result, the country's politicians and other wealthy Zimbabweans seek medical attention in South Africa or further abroad.
Mugabe leaves behind a chequered legacy.
A former liberation fighter who waged a guerilla war against white-minority rule in what was then Rhodesia, in later years Mugabe clung to power, becoming one of Africa's longest-ruling leaders.
Still revered by some on the continent for his fight against white domination, he is widely despised by others who see him as responsible for destroying the country's economy and violently oppressing any opposition.
He is survived by his children and politically-ambitious wife Grace - sometimes dubbed "disGrace" for her penchant for high-end shopping and a lavish lifestyle.
-------------------------------------------------------------------------