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. Hecker later testified before the United States Congress that while North Korea seems to have successfully extracted plutonium from the spent fuel rods, he saw no evidence at the time that they had actually produced a workable weapon. In 2007, the former senior scientist of Pakistan, Dr. Abdul Qadeer Khan claimed that North Korea's nuclear program was well advanced before his visit in 1993 with Benazir Bhutto, former prime minister.