Israel strikes slain Iranian Supreme Leader Ayatollah Ali Khamenei's underground military bunker

"The underground compound was created by the regime as a base for advancing military activities and its extremist ideologies against the State of Israel and the Western world," the IDF said. "It spanned multiple streets in the heart of Tehran and contained numerous entrances and meeting rooms for senior members of the Iranian terrorist regime."

Israel later released an illustrated video which showed a number of entry points throughout Tehran with tunnels leading to the underground bunker.

The official said that Khamenei spent millions of dollars and a number of years building the bunker, which he did not use on the morning of the strike. Sources familiar with the intelligence say that Khamenei believed no one had the guts to strike him.

Khamenei was killed on the first day of Operation Epic Fury after ruling the Islamic Republic for more than 30 years. During that time, he oversaw harsh internal crackdowns, including the most recent one in January, which targeted Iranian protesters, as well as international confrontations.

Fox News' Trey Yingst and Fox News Digital's Efrat Lachter and Ruth Marks Eglash contributed to this report.