Pope Benedict is urging nuclear-armed nations to get rid of their arsenals.
The pope issued the plea Saturday at the Vatican after Japan's new ambassador to the Holy See presented his credentials to the pontiff.
Pope Benedict called nuclear weapons a source of tension and mistrust. He said the 65th anniversary of bombings of the Japanese cities of Hiroshima and Nagasaki should serve as a reminder of the horror nuclear weapons can cause.
The United States dropped atomic bombs on both cities in August of 1945, killing more than 200.000 people. Japan surrendered unconditionally shortly afterwards, ending World War Two.
Pope Benedict praised Japan for setting an example since the bombings, for always trying to find peaceful solutions to conflicts.
Some information for this report was provided by AP and AFP.