North Korea said it reached an unspecified agreement with the U.S. this week on its nuclear weapons program, and America's top nuclear envoy expressed optimism Friday that progress could be made when wider arms talks reconvene, according to The Associated Press. North Korea's Foreign Ministry said meetings in Germany between U.S. envoy Christopher Hill and North Korea's main nuclear negotiator Kim Kye Gwan had been held «in a positive and sincere atmosphere and a certain agreement was reached there.» No further details were given. Hill said the talks Tuesday through Thursday in Berlin laid the foundations for progress when six-nation nuclear talks resume and that he had agreed with his North Korean counterpart «on a number of issues.» He declined to elaborate, and said the sessions had been more an exchange of views than negotiations.