LONDON (Reuters) - A television pool report by U.S. network NBC said on Monday that a U.S. Marine had shot dead an unarmed and wounded Iraqi prisoner in a mosque in Falluja. The Iraqi was one of five wounded prisoners left in the mosque after Marines had fought their way in on Friday and Saturday. There was no immediate comment from the Pentagon (news - web sites) on the report. U.S. forces launched an offensive one week ago on Falluja, and have gained overall control of the formerly rebel-held city, although scattered resistance remains. The pool report by NBC correspondent...