In another sign of warming relations between two wartime foes, a senior North Korean nuclear negotiator will attend a security conference in the United States, a U.S. official confirmed Thursday. Word of Ri Yong Ho's visit to the forum held by Syracuse University comes on the heels of a breakthrough agreement that will provide much-needed U.S. food aid to North Korea in exchange for a rollback of its nuclear programs. In this Feb. 11, 2012 photo, residents walk past posters with popular slogans illustrating North Korea's main policies, on a street in Pyongyang, North Korea. From left to right, they read "Let's march toward a military first revolution," "Let's accomplish the tasks laid out in this year's joint new year's editorial,' and "Devote the victors' hearts to the building of a strong nation." North Korea raised hopes Wednesday for a major easing in nuclear tensions under its youthful new leader, Kim Jong Un, agreeing to suspend uranium enrichment at a major facility and refrain from missile and nuclear tests in exchange for a mountain of critically needed U.S. food aid. (AP Photo/Jean H. Lee) Close The commander of U.S. forces in the Pacific, Adm. Robert Willard, said Thursday he is hopeful but not optimistic about the latest efforts to get North Korea to end its nuclear weapons program. "In the past we have not seen much change," Willard told a congressional hearing in Washington. In a possible sign of things to come, Ri, North Korea's vice foreign minister and envoy to nuclear disarmament negotiations, has been cleared to travel to the U.S. to attend the Syracuse University forum, The Associated Press was told in Seoul. While Syracuse University's Maxwell School of Citizenship and Public Affairs will hold the forum, its exact location was not known. U.S. State Department spokeswoman Victoria Nuland said the envoy was coming at the Maxwell School's invitation for three days next week to attend "track two," or unofficial discussions the school is sponsoring, starting Wednesday. "At the current moment there are no plans for official U.S. government meetings with the negotiator," she told a news briefing in Washington. The U.S. and North Korea do not have formal diplomatic relations, but the measures laid out in the deal announced Wednesday include facilitating "people-to-people" exchanges.