Iran is subject to various sanctions at numerous levels in the international system. This includes measures adopted by the UN Security Council, measures adopted by individual states, such as the US, and measures adopted by the EU.
The sanctions adopted by individual states are usually adopted as complementary measures to UN Security Council measures, which is allowed for under the various UN sanctions resolutions. Iran has taken the line, however, that UN sanctions are themselves illegal - citing the ostensible illegitimacy of the resolutions adopted by the Security Council.
The Security Council adopts sanctions under chapter VII of the UN Charter which deals with threats to international peace and security. Iran’s case, therefore, is that the country’s nuclear programme does not present a threat to international peace and security because it is purely peaceful in nature. However, the International Atomic Energy Agency has consistently failed to conclude that Iran’s programme is entirely peaceful in nature, which is why the Agency’s Board of Governors referred the case to the Security Council in the first place.
The bottom line is that, while Iran may maintain that its programme is and has been entirely peaceful in nature, the international community is not convinced. Iran therefore will continue to be subject to sanctions until the IAEA and other independent bodies are satisfied as to the nature of Iran’s programme.
The admission by Rouhani highlights the need for vigilance amongst the business community. As Iran is intent on continuing its prohibited activities, businesses must ensure that they do not conduct trade that would assist Iran in bypassing the sanctions.
 See http://www.bbc.co.uk/news/world-middle-east-28997452 (accessed 01/09/2014)