Iran appears to have stepped up its efforts to produce a nuclear weapon amid new information about its level of technological expertise and its dealings with North Korea, according to nonproliferation expert Leonard S. Spector. Iran has been able to enrich uranium to the 19.75 percent level, a significant step toward producing weapons-grade uranium. That Iran wants to enrich all of its uranium supply to this level "“ beyond what it would likely need for medical isotopes "“ suggests the desire and wherewithal to build a nuclear weapon. Moreover, recent revelations that North Korea has delivered uranium concentrate called yellowcake to Iran via Syria and Turkey is further evidence of Iran's nuclear intentions and threatens the current nonproliferation regime. Response to this...