The United States and North Korea have toughened their stands in their dispute over the North’s nuclear programs, a Russian negotiator said on Wednesday, while South Korea urged its northern rival to be more flexible. Envoys to six-party working-level talks on ending the North Korean nuclear crisis met for the first time in the Chinese capital but analysts saw scant chance of a breakthrough with Pyongyang demanding rewards for freezing its atomic programs. Neither North Korea nor the United States, the two protagonists in the standoff, have shown any willingness to budge from their positions during the inaugural working-level talks that are intended to pave the way for higher-level meetings. “Their positions are even tougher than they were several days ago,” Valery Sukhinin, who is leading the Russian delegation to the talks, told Itar-Tass news agency in Beijing. Full Story