U.S. officials were looking for concrete signs that nuclear-armed North Korea is willing to take "irreversible steps" to give up its nuclear weapons programs as the two sides began a second day of talks Friday. Ambassador Stephen Bosworth, the Obama administration's top envoy on North Korean affairs, and North Korean Vice Foreign Minister Kim Kye Gwan remained silent after meeting behind closed doors on Thursday at the U.S. Mission to the United Nations for a total of about five hours. The State Department called the talks "serious and business-like." The U.S. wants to determine if North Korea is ready to fulfill its commitments under a 2005 joint declaration requiring the North to abandon all nuclear weapons programs and allow the return of international weapons inspectors. In exchange, Pyongyang would get better relations with its Asian neighbors, energy assistance, and a pledge from Washington that its troops won't attack the North.