"With great honour, I declare that as of today our dear country has joined the nuclear club of nations and can produce nuclear fuel on an industrial scale," Mr Ahmadinejad said.
However the US has expressed concern at the comments that come despite pressure upon Iran from the UN security council, which has imposed deadlines on the country to stop its uranium enrichment programme.
Tehran has consistently denied that it is using its nuclear facilities for making weapons such as atomic bombs but for the peaceful production of nuclear energy.
"We are very concerned about Iran's announcement that they entered an 'industrial stage' of nuclear fuel production," said Gordon Johndroe of the White House's national security council.
Calling on Iran to "comply with its obligations to the International Atomic Energy Agency (IAEA) and UN security council", Mr Johndroe added that, in contrast to "joining a nuclear club of nations", Iran will be isolating itself from the international community through its nuclear enrichment program.
"Iran continues to defy the international community and further isolate itself by expanding its nuclear program, rather than suspending uranium enrichment," the White House spokesman said.
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