Tehran - The head of the United Nations atomic agency on Sunday said Iran was carrying out its commitments made under a landmark nuclear deal with world powers."As of today, I can state that the nuclear-related commitments made by Iran under the JCPOA (nuclear deal) are being implemented," Yukiya Amano said at a press conference in Tehran broadcast by state television.The 2015 accord, signed by the Islamic republic as well as Germany, Britain, China, France, Russia and the United States, saw economic sanctions on Iran lifted in exchange for it curbing its nuclear activities.This month, US President Donald Trump said a "total termination" of the deal remained possible, after refusing to certify the accord and leaving its fate to the US Congress.On Sunday, Amani met Iran's President Hassan Rouhani, Foreign Minister Mohammad Javad Zarif and Iran's Atomic Energy Organisation chief Ali Akbar Salehi.According to the government's website, Rouhani told the head of the International Atomic Energy Agency that Iran wanted to "cooperate with the IAEA long term"."We want to continue with the nuclear accord and avoid (the United States) disturbing it," Salehi said."If the nuclear deal is broken, it will have unpredictable consequences."The 2015 accord included a ban on high-level uranium enrichment - 20% or more - that would take Iran close to the level needed for a nuclear weapon. Salehi said that Iran could resume uranium enrichment of 20% within four days if it wished."But we don't want that," he said.Under the deal, Iran is allowed to enrich uranium to low levels of 3.5%, which can be used to power reactors.At 20%, uranium can be used for nuclear medicines, but crucially leaves only a small amount of work to get to the 90% level needed for a nuclear weapon.