Tehran, July 18 -- Iran's Supreme Leader Ayatollah Mojtaba Khamenei on Saturday (local time) launched a scathing attack on the United States, calling it the "Great Satan" and declaring that the signature of US President Donald Trump on the 14-point memorandum of understanding was "utterly worthless".

Khamenei also warned that Iran and its "Resistance Front" have "unforgettable lessons" in store if Washington continues its military strikes on the Islamic Republic.

In a message addressed to the Iranian nation, Khamenei accused the United States of repeatedly violating agreements with Iran, saying the breaches had once again exposed Washington's "dishonesty, irrationality, unreliability, and malicious nature."

"The repeated breaches of th...