The chief UN nuclear negotiator, in Pyongyang for talks on how North Korea will close its main atomic reactor, was unable to meet with the country's top nuclear negotiator Wednesday because of scheduling problems, the agency's spokeswoman said. Mohamed ElBaradei, head of the Vienna-based International Atomic Energy Agency, had been slated to meet with North Korean Vice Foreign Minister Kim Kye Gwan, IAEA spokeswoman Melissa Fleming said in a telephone interview. They said "he was busy preparing for the six-party talks," Fleming said from Pyongyang. The next round of the international disarmament talks on the North's nuclear ambitions is scheduled to begin Monday in Beijing. Instead, ElBaradei met with Vice Foreign Minister Kim Hyong Jun, she said.