Iranian journalist Mohamad Ahwaze reported the major political move on Twitter, citing sources in the country. Writing in Arabic, Ahwaze said Khamenei had handed power over to his son, Mojtaba Khamenei.

“Iranian President Hassan Rouhani was scheduled to meet on Friday with the Iranian Leader Khamenei, this meeting between [Khamenei] and President Rouhani was canceled due to the deterioration of Khamenei’s health condition,” Ahwaze wrote.

Ahwaze went on to explain that the cause of the supreme leader’s ill health was not known but suggested it could be due to prostate cancer. Khamenei reportedly deteriorated over night.