Beatrice Fihn, executive director of the 2017 Nobel Peace Prize-winning International Campaign to Abolish Nuclear Weapons, is pictured in Geneva on Oct. 2, 2020. (Kyodo)

TOKYO - Activists urged Japan on Saturday to join a U.N. treaty banning nuclear weapons, as they celebrated the coming into force of the 52-member pact as a boost for the global disarmament movement.