Iraq's parliament, which had been due to elect the country's president on Wednesday, postponed the vote by a day, delaying the formation of a power-sharing government urgently needed to confront a Sunni Muslim uprising, Reuters reported.
The advance by Sunni Islamist militants who seized swathes of northern Iraq last month has put Iraq's survival in jeopardy. Its politicians have been deadlocked over forming a new government since an election in April.
Washington has made clear that setting up a more inclusive government in Baghdad is a requirement for its military support against the insurgency. Under Iraq's governing system, in place since the post-Saddam Hussein constitution was adopted in 2005, the prime minister is a member of the Shi'ite majority, the speaker a Sunni and the largely ceremonial president a Kurd.
Parliament Speaker Salim al-Jubouri told the chamber that the Kurds had asked for a one-day delay on the vote so they could agree on a candidate.
The Sunni insurgency is led by Islamic State, which shortened its name from the Islamic State in Iraq and the Levant (ISIL) after last month's advance and declared its leader "caliph" - ruler of all Muslims.
It now controls a swathe of territory from Aleppo in Syria close to the Mediterranean to the outskirts of Baghdad.
Washington hopes a more inclusive government in Baghdad could save Iraq by persuading moderate Sunnis to turn against the insurgency, as many did during the "surge" offensive in 2006-2007 when U.S. troops paid them to switch sides.