A landmark deal to strictly curb Iran’s nuclear programme can be built upon to ensure universal ratification of a global treaty to ban all nuclear tests.

That’s according to Lassina Zerbo, Executive Secretary of the Comprehensive Nuclear-Test Ban Treaty Organization, CTBTO.

Iran signed an international accord in July to significantly limit the country’s nuclear ability for more than a decade.

Mr Zerbo said the nearly 20-year old test ban treaty is being held “hostage” by eight specific nations with nuclear technology that must join it before it can take effect.

Cristina Silveiro spoke with him about progress in ending nuclear testing and bringing the treaty into force.

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