The head of an antinuclear group has urged Japan to attend the first meeting of parties to a U.N. treaty banning nuclear weapons, saying the only country to have suffered atomic bombings has a "moral responsibility" to do so.

In a recent online interview, Beatrice Fihn, executive director of the International Campaign to Abolish Nuclear Weapons, said that, as an observer, Japan should "discuss issues relevant to survivors of nuclear weapons use" at the meeting as it has "the knowledge and expertise."

The first meeting on the pact outlawing the development, testing, possession and use of nuclear weapons is expected to be held in Austria within a year of the treaty going into force on Jan. 22.