saying the world must step up pressure on tehran. the point of the pressure is to bring the iranians back to the negotiating table, and to resolve the issue in a way that prevents iran from having nuclear weapons. martha: president mahmoud ahmadinejad still insisting that this enrichment is also for peaceful purposes. amy kellogg has spent time inside iran, knows it well and joins us now live from london. amy? reporter: martha, it is well-known that iran does need 20% enriched uranium for the research center in tehran but the a renowned, respected nonproliferation expert told me while iran will be able to enrich it 20%, it won t have the technology to actually package the fuel into the rods needed for the medical research reactor. so this is just another reason a lot of people have further suspicions about the true nature