(CNN) -- Iran can't convince the world it doesn't want nuclear weapons as long as it is producing nuclear fuel on an industrial scale, former U.N. weapons inspector Hans Blix said Wednesday.
Iran has defied a U.N. Security Council demand that it halt its uranium enrichment program, insisting it has a right to produce fuel for civilian power plants. But while Iran says it has no intention of producing nuclear weapons, "they could change their mind tomorrow," Blix told CNN's "Amanpour" program.
"I don't think they can convince the world about it, and only a termination or strict control of the enrichment process could calm the world," Blix said.
Industrial-scale uranium enrichment could also give the Islamic republic the capability to produce weapons-grade uranium, a more difficult task. The United States and Israel have accused Iran of working toward a nuclear bomb, and Iran has so far balked at an international proposal to send its uranium stocks to Russia and France for conversion into fuel for medical research and treatment.
"The fact is that that enrichment very much increases tension in the Middle East, and it may even lead to other countries in the Middle East thinking of going for enrichment," Blix said. But he said the United States "holds the key" to breaking the impasse, and could convince Iran to halt its nuclear fuel program by offering security guarantees or a resumption of diplomatic relations with Tehran.
Blix led the U.N. effort to find Iraq's suspected nuclear, chemical and biological weapons programs before the 2003 invasion of Iraq. His reports that no such weapons were turning up were discounted by the United States, which insisted those programs were being concealed. After the invasion, Iraq was found to have dismantled its weapons programs years before.