Zimbabwe’s ailing opposition leader Morgan Tsvangirai on Wednesday appointed one of his three deputies to take charge of the party while he undergoes treatment in South Africa.

Nelson Chamisa was appointed to lead the Movement for Democratic Change (MDC) party, until Tsvangirai returns, his spokesman Luke Tamborinyoka said in a statement.

“This is in light of the president’s absence and that of the two other vice presidents who are both in South Africa,” Tamborinyoka said.

On Tuesday this week, a party source disclosed that Tsvangirai’s condition is critical and his supporters should “brace for the worst.”

On his Twitter, the 65-year-old Tsvangirai refuted the claims that he is critically ill, stating that he was shocked by what he read from the media.

“Of course I have cancer and not feeling too well but I am stable and the process is under control,” Tsvangirai said in a post on twitter, adding that “I am recovering.” He wrote.

I am shocked to read in the press that I am in a critical condition. Of course I have cancer and not feeling too well but I am stable and the process is under control. I have been frequently on twitter of late, I am recovering.

— Morgan Tsvangirai (@mrtsvangirai) February 6, 2018

In 2016 Tsvangirai disclosed he was suffering from colon cancer and has since been in and out of hospital.

Early January he returned to Johannesburg for treatment and doctors said that he was critical.