Pope Francis is eager to deliver a message from one of Japan's two atomic-bombed cities that the making of nuclear weapons -- not just their use or possession -- is unethical, according to a Japanese Catholic source.

The pope plans to visit Japan in November, making him the first pontiff to travel to the country since John Paul II nearly 40 years ago. He may also go to Hiroshima and Nagasaki -- the cities that suffered U.S. atomic bombings in the final days of World War II.

Referring to the pope's ongoing efforts to call for a world without nuclear weapons, the source said, "The pontiff is expected to go a step further."

Pope Francis, elected as the Roman Catholic pontiff in 2013, condemned not only the use of nuclear weapons but their "possession" for the first time in his speech in 2017. The Catholic Bishops' Conference of Japan said there are no official records that the pope went so far as to criticize the making of nuclear armaments.

The source hopes that the pope's remarks, possibly to be made in Nagasaki, will give fresh impetus to the nuclear disarmament movement at a time when concerns over a new nuclear arms race are growing following the U.S. announcement of its withdrawal from a nuclear arms control treaty with Russia.

A landmark U.N. treaty outlawing nuclear weapons was adopted in 2017, but has yet to enter into force. Japan, which relies on the U.S. nuclear deterrent for protection, and the world's nuclear weapons states are among the countries that have not ratified the pact.

"If the pope conveys what is right, it will have a worldwide impact," said Akira Kawasaki, a steering committee member of the International Campaign to Abolish Nuclear Weapons, which won the 2017 Nobel Peace Prize for its efforts that led to the adoption of the treaty.