Zimbabwe’s main opposition leader Morgan Tsvangirai is critically ill in a South African hospital, reports say.

Local media quoted family sources as saying the 65-year-old former prime minister – who is being treated for colon cancer – is suffering from weight loss, exhaustion and muscle thinning.

During his political struggle against ex-President Robert Mugabe, he has been beaten and imprisoned numerous times.

Mr Tsvangirai heads Zimbabwe’s Movement for Democratic Change (MDC) party.

He has been in and out of hospital since June, receiving treatment in a Johannesburg hospital for cancer. He returned to the hospital early last month.

Mr Tsvangirai’s health deteriorated rapidly on Monday, family sources told Zimbabwe’s Bulawayo24 news website on Tuesday.

He had lost appetite and had difficulty eating or swallowing fluids, the sources said. Mr Tsvangirai also reportedly had breathing problems.

Meanwhile, an MDC party source was quoted by Reuters news agency as saying that Mr Tsvangirai “is critically ill and we should brace for the worst”.