 As late as the end of 2003, North Korea claimed that it would freeze its nuclear program in exchange for American concessions – in particular a non-aggression treaty – but a final agreement was not reached and talks continued to be cancelled or fall through.North Korea withdrew from the Nuclear Non-Proliferation Treaty in 2003 after not receiving light-water reactors promised by the United States which were going to be delivered in exchange for North Korea not developing their own power plants, as understood in the "Agreed Framework".In early 2004 former Los Alamos National Laboratory director Siegfried S. Hecker, as part of an unofficial U.S. delegation, was allowed to inspect North Korea's plutonium production facilities.