Widespread media reports show that Mojtaba Hosseini Khamenei, the son of Iran’s slayed Supreme Leader Ayatollah Ali Khamenei, has either been chosen to replace his father or was the clear front-runner to do so.

Ayatollah Ali Khamenei, 86, was killed Saturday, at the start of the U.S. and Israeli bombing campaign in Tehran, the Iranian capital. 

The younger Khamenei, aged 56, has long been seen as a “shadow power” in Iran, rarely seen in public but an influential, hard-line figure behind the scenes in terms of domestic and international policy and strategy. If he is indeed selected to replace his father, it would be seen as a major blow to reformers inside the country as well as to Iranian opposition efforts from outside the country.

President Donald Trump has said one of the goals of the four-day-old U.S.-led campaign against Iran is to topple the ruling regime. 

If that does not happen immediately, it means that whoever emerges as Iran’s next Supreme Leader will be just the third person to hold that position since the 1979 Islamic Revolution, which deposed Mohammad Reza Pahlavi as Shah.

Iran’s first Supreme Leader was Ruhollah Khomeini, who ruled for ten years. He was replaced by Ayatollah Ali Khamenei, who was Supreme Leader from 1989 until his death Saturday.