FACTBOX-Security developments in Iraq

(Reuters) - Following are security developments in Iraq at 6 p.m. British time on Thursday:

* denotes new or updated item.

* FALLUJA - A U.S. marine was killed in combat in Anbar province on Wednesday, the U.S. military said.

* BAGHDAD - Iraqi special forces, backed by U.S. troops, captured three suspects believed to be involved in a bomb attack that destroyed Baghdad's Sarafiya bridge last month, the U.S. military said.

DUBAI - The self-styled Islamic State in Iraq, an al Qaeda-led militant group, posted a video showing the killing of nine abducted Iraqi police and army officers, after an ultimatum it gave to the Iraqi government expired.

ANBAR PROVINCE - U.S. forces killed one insurgent and detained two others during raids in Anbar Province while targeting a chemical bomb network and smuggling operations, the U.S. military said.

NEAR RAMADI - Iraqi police cleared al Qaeda militants from a town near the city of Ramadi, 110 km (68 miles) west of Baghdad, police colonel Dawud al-Faraji said. They arrested 56 insurgents, seized 950 passports and found a mass grave.

BAGHDAD - The Iraqi army killed two insurgents and arrested six others during the past 24 hours in different parts of Iraq, the Defence Ministry said.

BAGHDAD - Police said they found the bodies of 21 people shot dead in various districts of Baghdad on Wednesday.