Zimbabwe’s main opposition leader Morgan Tsvangirai is battling life threatening cancer in a South African hospital.
The 65-year-old is critically ill in the hospital, where he has been receiving treatment for colon cancer.
His supporters should “brace for the worst”, a source told Reuters news agency.
“From the medical report that I received yesterday the situation is not looking good,” the source said.
Mr Tsvangirai, who founded Zimbabwe’s Movement for Democratic Change (MDC) party, has been a key figure in opposing the country’s ousted former president Robert Mugabe.
Speaking last year, he claimed he had survived a number of assassination attempts and had been subjected to brutal beatings over the years.
His wife Susan was killed in a car crash in 2009, in which he suffered non-life threatening injuries.
Mr Tsvangirai, who confirmed he had colon cancer in June 2016, returned to Johannesburg in January for his latest round of treatment.
His illness has divided the MDC party, with officials publicly jockeying to succeed the former trade union leader.
Last month, Mr Tsvangirai said it was time for the older generation to step back and make way for “new hands”, raising prospects of leadership change.
Without its founder at the helm, the MDC is likely to face immediate instability and could even split, handing a gift to Zimbabwe’s new president Emmerson Mnangagwa in an election expected within the next six months.