Ayatollah Ali Khamenei comments.

Iran's policies of standing up to the United States have set off a "powerful bomb in the world of politics" bigger than the atom bomb dropped on Hiroshima, Supreme Leader Ayatollah Ali Khamenei said.
The comments, carried by state television and radio, come amid prolonged tension between Washington and Tehran over Iran's nuclear program. U.S. officials say Iran is trying to build an atom bomb but Tehran insists its plans are peaceful.
Iran has refused to halt sensitive nuclear work, despite U.S. threats to ratchet up pressure with new U.N. sanctions. Two rounds of sanctions have already been imposed since December.
U.S. and Iranian officials are due to hold a rare face-to-face meeting on May 28 in Baghdad. But both sides say the talks will focus on Iraqi security, not other issues.
Washington accuses Tehran of fuelling the violence in Iraq, a charge Tehran dismisses. Iran blames the U.S. occupying forces for the bloodshed.
Khamenei is the highest authority in Iran under its system of clerical rule.
The United States dropped a nuclear bomb on Hiroshima and another on Nagasaki shortly before Japan surrendered at the end of World War Two.
It cut ties with Iran after the 1979 Islamic Revolution.