Prime Minister Fumio Kishida and former U.S. President Barack Obama on Saturday called for a world without nuclear weapons amid Russian threats to use such weapons in the war in Ukraine and North Korea's rapid pace of missile tests.

They made the call in separate messages sent to the inaugural meeting of a nuclear disarmament forum comprising former political leaders and scholars in Hiroshima, which was devastated by a U.S. atomic bomb in the closing stages of World War II.

"We owe it to our children to pursue a world without nuclear weapons," Obama said in a video message to the two-day meeting through Sunday.