Israel sees Iran's nuclear program as a threat to its existence and has not ruled out military action if diplomacy fails to curb the Islamic Republic's atomic work.
The United States and other western powers suspect Iran is pursuing a nuclear weapon and are currently discussing the imposition of new economic sanctions against Tehran.
Iran says its nuclear program is peaceful and aimed at generating electricity.
"Israel or the United States cannot just bomb Iran and (expect) things to continue normally," Sheikh Naim Kassem told Reuters. "Any attack on Iran could ignite the whole region and the assailant will pay a heavy price whether its Israel or the United States."