US threatens toughest sanctions on Iran; Tehran vows retaliation

The United States has threatened Iran with its toughest sanctions yet, warning any country doing business with Tehran will face severe economic consequences. Washington aims to collapse the Iranian government through unprecedented economic pressure, with Treasury Secretary Scott Bessent calling for global cooperation. Iran has vowed retaliation against any nation joining US sanctions, with security official Mohsen Rezaei warning of "seismic" responses. Tehran threatened to block Gulf oil exports if neighbors participate. China has urged diplomatic solutions, while Gulf states remain cautious about joining Washington's campaign. Analysts note limited US leverage over China and Russia, Iran's major trading partners. China purchased 80 percent of Iran's shipped oil in 2025, with some sectors minimally reliant on the American financial system.