Nov 17 (Reuters) - Following are security developments in Iraq at 1300 GMT on Saturday. * denotes new or updated item * BAGHDAD - U.S. forces killed one gunman during operations in Rashidiya, just north of Baghdad, targeting so-called "special groups," the U.S. military said, referring to the rogue Mehdi Army units the United States believes are backed by Iran. * DIWANIYA - Iraqi forces arrested 12 gunmen and discovered weapons caches on Friday, the first day of an Iraqi army and police operation in Diwaniya, 180 km (110 miles) south of Baghdad, the Iraqi army said. BAGHDAD - U.S. forces killed six gunmen and detained 10 others during operations in central and northern Iraq, the U.S. military said. BAGHDAD - Four bodies were found on Friday in different areas in Baghdad, police said. NEAR HAWIJA - A roadside bomb targeting Iraqi troops wounded four Iraqi soldiers on Friday near Hawija, 70 km (43 miles) southwest of Kirkuk, the Iraqi army said. (Editing by Missy Ryan)