Updated

A diagram obtained by The Associated Press shows that Iranian scientists have run computer simulations for a nuclear weapon that would produce more than triple the explosive force of the World War II bomb that destroyed Hiroshima.

The diagram was leaked by officials of a country critical of Iran's atomic program to bolster their arguments that Iran's nuclear program must be halted before it produces a weapon. They provided the diagram only on condition that they and their country were not named.

The International Atomic Energy Agency — the Vienna-based U.N. nuclear watchdog — reported last year that it had obtained diagrams indicating Iran was calculating the "nuclear explosive yield" of potential weapons.