Defense Secretary David Petraeus says U.S. troops in midst of `` mission transition '' Gen. Odierno taking over command in U.S. from Gen. David Petraeus . Ray Odierno expected to set stage for eventual Iraq withdrawal .
Defense Secretary Robert Gates says U.S. troops in midst of `` mission transition '' Gen. Ray Odierno taking over command in Iraq from Gen. David Petraeus . Odierno expected to set stage for eventual U.S. withdrawal .