BAGHDAD, Iraq, March 12 - In the weeks after Baghdad fell in April 2003, looters systematically dismantled and removed tons of machinery from Saddam Hussein's most important weapons installations, including some with high-precision equipment capable of making parts for nuclear arms, a senior Iraqi official said this week in the government's first extensive comments on the looting. The Iraqi official, Sami al-Araji, the deputy minister of industry, said it appeared that a highly organized operation had pinpointed specific plants in search of valuable equipment, some of which could be used for both military and civilian applications, and carted the machinery...