Iran vows 'unimaginable' attack on US mainland; FBI warns of West Coast drone threat.

• Conflict between Iran, America, and Israel intensifies after Ayatollah Khamenei's assassination, with Iran retaliating strongly.
• FBI warns California Police Department of a potential Iranian drone attack on America's 'West Coast'.
• Sources suggest Iran might use an unknown vessel near the US coast for a sudden drone attack on California.
• US President Donald Trump dismisses the FBI warning, stating he is not worried about an attack on American soil.
• The escalating conflict, with threats reaching the US mainland, raises fears of a potential World War III.