Iran can resume high-level uranium enrichment within five days if the United States tears up the nuclear deal, the head of its Atomic Energy Organisation said Tuesday.

"If we make a determination, at most in five days we can start 20-percent enrichment in Fordo (nuclear plant)," said Ali Akbar Salehi in an interview with state broadcaster IRIB.

"Of course we would not like such a thing to happen as we made a lot of effort to achieve the JCPOA (nuclear deal)," he added.