The 85-year-old supreme leader of Iran, Ayatollah Ali Khamenei, is gravely ill, adding to the uncertainty of an Iranian response to Israel’s weekend attack on their military installations, a report published Saturday in The New York Times said.

According to the report, the most powerful political authority in the Islamic Republic is seriously ill, and there is internal turmoil over the possibility that his second son, Mojtaba, 55, might succeed him.

The younger Khamenei served in the Iran–Iraq War from 1987 to 1988, and reportedly took control of the militia that was used to suppress the protests surrounding the result of the 2009 elections, which demonstrators said was rigged.