VIENNA — 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, according to a diagram obtained by the Associated Press.

The diagram was leaked by officials from 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. The officials provided the diagram only on condition that they and their country not be named.