Why would Iraqi officials go behind U.S. Baghdad command to buy black market arms?

An Iraqi carries a Russian-designed machine gun at a funeral, July 27, 2007, in Karbala, an Iraqi city dominated by Shiite Muslim militias. Italian authorities have broken up an alleged illegal plot to ship 5,000 such machine guns, along with 100,000 assault rifles, into Iraq. Iraqi police supposedly would have been the end users, but Shiite militias are known to have obtained weapons through police channels. (AP Photo/Ghassan al-Yassiri, File)

For one thing, The Associated Press has learned that Iraqi government officials were involved in the deal, apparently without the knowledge of the U.S. Baghdad command _ a departure from the usual pattern of U.S.-overseen arms purchases.

Why these officials resorted to "black" channels and where the weapons were headed is unclear.