Baghdad, Iraq ? In another dramatic last-minute standoff, Iraqi leaders put off a vote on a draft constitution late Monday, adjourning Parliament at a midnight deadline in a bid for more time to win over the Sunni Arab minority whose support is key to stopping the insurgency.

The Shiite-Kurdish faction that submitted the draft constitution expressed optimism that a deal was still possible within a few days. But top Sunni Arab leaders said flatly that compromise was far off.

More than 20 issues still divide the sides, said Saleh al-Mutlaq, one of four top Sunni Arab negotiators. Those issues include federalism, power-sharing and even how the constitution should speak about Islam.

“This constitution will divide the country,” al-Mutlaq said.

The numerous remaining issues cast doubt whether the Iraqis would be able to finish the document within a few days since the various groups have widely differing positions. Repeated delays are a deep embarrassment for the Bush administration at a time of growing doubts within the United States over the mission in Iraq.

The U.S. military said two U.S. soldiers from Task Force Liberty were killed Monday by a roadside bomb during a combat patrol north of Baghdad, and two more soldiers died when their vehicle overturned during a military operation near Tal Afar. At least 1,870 U.S. troops have died since the Iraq war started in 2003, according to an Associated Press count.

Washington had applied enormous pressure on the Iraqis to meet the original Aug. 15 deadline but parliament instead had to grant a week’s extension, which they again failed to meet.

The Shiite-Kurdish draft would fundamentally transform Iraq from the highly centralized state of Saddam Hussein into a loose federation of Kurds, Shiites and Sunni Arabs. The Sunnis – who dominated Iraqi society under Saddam – oppose that decentralization, fearing it would cut them out of the country’s oil wealth and leave them powerless.

On the issue of Islam, al-Mutlaq said Sunni Arabs objected to the draft because it called Iraq an Islamic country and not an Islamic and Arab country. The Kurds are mostly Sunni Muslims but they are not Arab.

The Shiite-Kurdish faction finished the draft on Monday and formally submitted it to parliament as the lawmakers convened minutes before a midnight deadline. But the negotiators quickly withdrew the draft because of the fierce Sunni Arab resistance.

The 15 Sunni Arab members of the drafting committee issued a statement early Tuesday saying they had rejected the constitution because the government and the committee did not abide by an agreement for consensus.