Belgium has announced it will attend the first meeting of state parties to the Treaty on the Prohibition of Nuclear Weapons as an observer.
The UN treaty banning nuclear weapons went into effect in January 2021. It has been ratified by more than 60 countries and territories.
The first meeting of state parties to the treaty will open in the Austrian capital Vienna on Tuesday.
Belgium's ruling coalition parties had earlier agreed to look at how the nuclear weapons ban treaty could contribute to multinational nuclear arms reductions.
Belgium is a member of the North Atlantic Treaty Organization, which is headquartered in the Belgian capital Brussels.
NATO maintains that a world free of nuclear arms is one of its goals, but says it will keep them in its arsenal as long as other nations possess them.
The other NATO members that plan to attend the meeting as observers are Germany and Norway.
Japan, which is the only country to have suffered atomic bombings, has decided not to attend the meeting as an observer.