Iran vowed Tuesday to seek "important changes" in a United Nations plan that would require it to ship its enriched uranium out of the country for processing abroad, raising alarm among Western governments involved in nuclear talks with the country.

Iran sidestepped a Friday deadline on a U.N.-drafted agreement that would ship much of the country's uranium to Russia for enrichment, saying it would prefer instead to buy nuclear fuel from foreign suppliers for a reactor to make medical isotopes.