According to Arab intelligence that confirmed the reports, the submarine passed the Red Sea and was making its way towards the Persian Gulf.
President-elect Joe Biden will have to see if he can reestablish the agreement once he assumes office, after Trump withdrew from it on May 8, 2018.
The Islamic Republic has given contradictory details of Fakhrizadeh's death in a daytime Nov. 27 ambush on his car on a highway near Tehran.
Assassinating Iranian nuclear scientists is a form of Israeli self-defense. Assassinating the father of the Iranian nuclear weapons program was an ethical act.
Will Iran now get dangerously close to a bomb?
"It wasn't a simple terror attack," he said. "The scene looked like a war zone."
One scientist was warned not to walk the same routes regularly and to be mindful of strange packages or unusual events.
"There is a concern Iran will try to act in this way against Israeli destinations,” the NSC cautioned.
BEHIND THE LINES: A conventional response from the Iranian state forces, which would amount to a declaration of war, is unlikely.