Baghdad, Iraq ? Five of the top Sunni Arabs in Iraq’s government spoke out Saturday against the draft constitution, delivering a major blow to last-minute efforts to craft a document that can win the backing of all ethnic and political groups.

Their statement came shortly after Sunni negotiators offered their own proposals on the deal-breaking issues of federalism and the fate of former ruling party members as U.S. diplomats worked furiously to mediate a deal on the eve of a parliament session to sign off on the draft.

U.S. officials pressed the Shiite Muslim, Kurdish and Sunni Arab delegations to reach a consensus so the National Assembly can be presented a document acceptable to all – enhancing chances for easy approval by voters in an Oct. 15 referendum.

Shiite and Kurd leaders already accepted the draft, but parliamentary approval over objections by the Sunni minority would be a severe blow to President Bush’s hopes that a new constitution will lure Sunnis from the insurgency.

There was no comment on the new Sunni proposals from Shiites and Kurds, who said compromises on federalism and purging Baath Party members that they submitted Friday were their final offers. Sunni negotiators said Saturday that those revisions were unacceptable.

Prospects for a compromise dimmed when four Sunni Arab members of the Cabinet and a Sunni deputy prime minister declared that they objected to 13 provisions in the draft – more points than Sunni negotiators cited in talks Friday.

Iraq's deputy prime minister Abed Mutlaq al-Jbouri, left, and culture minister Nouri Farhan al-Rawi read a document Saturday after a news conference in Baghdad, Iraq. Four Sunni Arab Cabinet ministers and one Sunni deputy prime minister expressed reservations Saturday about the draft constitution, citing 13 points they said in a statement need amending.

Among other things, the five Sunnis objected to measures reserving government posts for members of specific religious groups, demanded postponement of any decision on federalism, wanted all references to Saddam Hussein’s Baath Party removed and insisted the constitution identify Iraq as an Arab – and not just an Islamic – country.

The statement was issued by Culture Minister Nouri Farhan al-Rawi, Minister of State for Women’s Affairs Azhar Abdel-Karim, Minister of State for Provincial Affairs Saad al-Hardan, Industry Minister Osama al-Najafi and Deputy Prime Minister Abed Mutlaq al-Jbouri.

Although the five were not directly involved in the negotiations, the statement was significant because of their stature in the community. If Sunnis of such rank find the draft objectionable, it is questionable whether supporters could sell the document to rank-and-file Sunni voters.

Sunnis account for only 20 percent of Iraq’s 27 million people, but they are in a strong position to derail the constitution. If two-thirds of voters in any three provinces reject the charter in the referendum, the constitution will be defeated, and Sunnis have the majority in at least four provinces.

Unless there are further changes, Sunni leaders said their people should oppose the charter peacefully by voting “no” in the referendum.

Al-Hassani, the parliament speaker, said he planned to convene the legislature today but no hour was announced. It was unclear whether the draft would be put to a vote in the assembly.

The speaker said Shiites and Kurds sought to address Sunni concerns by offering Friday to put off consideration of federalism until after a new parliament is elected in December, when Sunnis are expected to expand on the 17 seats they won Jan. 30 after many boycotted that vote.

Sunni negotiator Fakhri al-Qaisi said his side saw no “essential change” in those areas and submitted their own proposed wording.