U.S. Ambassador says he 's seen private security contractors overreact . Iraqi authorities say Blackwater guards fired indiscriminately , killing as many as 20 civilians ; Blackwater says its employees responded properly to an insurgent attack on a convoy . Defense Secretary says he wants closer monitoring of security contractors in Iraq . Iraqi officials look after civilians killed by Blackwater USA guards . Blackwater says its headquarters were raided .
U.S. Ambassador says he 's seen private security contractors overreact . Defense Secretary says he wants closer monitoring of security contractors in Iraq . Iraqi officials look after civilians killed by Blackwater USA guards . Blackwater says its headquarters were raided .