As the topic, Iran will lead the UN Conference on Disarmament at the end of the month. The UN Conference was begun in Geneva in May 13th, and Iranian Ambassador, Seyed Mohammad Sajjadi, will lead the conference from May 27th to June 23rd.
From the past records of conference, they have discussed about such related topics that are mainly about multilateral arms control and disarmament agreements. For instance, they've made the Treaty on the Non-Proliferation of Nuclear Weapons and the Stockpiling and Use of Chemical Weapons.
Some countries have defied the international community over its nuclear program and usually are under the sanctions, such as North Korea.
From the Spokesperson of US. Mission's words, the United States believe countries that are conflict with Chapter VII sanctions for weapons proliferation or human-rights should be barred and Iran's rotation's highly inappropriate.