Panetta to discuss Iraqi troop levels

ROBERT BURNS AP National Security Writer BAGHDAD The U.S. will not "walk away" from the challenge of Iran's stepped-up arming of Iraqi insurgents who are targeting and killing American troops, U.S. Defense Secretary Leon Panetta said Monday. "We're very concerned about Iran and the weapons they're providing to extremists in Iraq," he told a small group of soldiers on his first visit to Iraq as