Iraqi Kurdish, Sunni and Shi'ite negotiators are holding marathon talks, in a push to reach agreement on a draft constitution ahead of a Monday night deadline.
Negotiators have been unable to bridge differences over issues of political autonomy, revenue distribution and the role of Islamic law in post-war Iraq.
An Iraqi government spokesman, Laith Kubba, says if negotiators fail to reach agreement by midnight Monday that lawmakers may have to amend the constitution to extend negotiations for a second time.
Meanwhile, the U.S. military says it has opened a criminal probe into the death of a relative of Iraq's ambassador to the United Nations. The son of Ambassador Samir Sumaidaie's cousin was killed in June as U.S. Marines searched his home in western Iraq.
Last month, the ambassador called the killing of Mohammed Sumaidaie a crime and demanded a full investigation.
Some information for this report provided by AP.