Iraq's parliament delayed debate on Sunday on a divisive draft law on federalism that minority Sunni Arabs fear could lead to the partition of Iraq and stoke sectarian conflict that has already killed thousands.
The Shia and Kurdish-sponsored draft law paves the way for Iraq's 18 provinces to form autonomous federal regions with their own governments and security forces. Kurdistan, encompassing three provinces in northern Iraq, is already largely autonomous and has its own president and parliament.
But Sunnis, concentrated in Iraq's resource-poor central and western provinces, are opposed to such a move, fearing it would seal their political doom by giving Shias in the south and Kurds in the north control of much of Iraq's oil.
"We stand against this law. This law wants to divide Iraq," Adnan al-Dulaimi, leader of the biggest Sunni Arab bloc in parliament, the Iraqi Accordance Front, said on Sunday.
Kurdish and Shia politicians drew their own battle lines, insisting the draft law, which was to have had its first reading on Sunday, would go before parliament on September 19, a date they said had originally been agreed by the Sunni parties.
"We will not retreat," said Shia deputy speaker Khaled al-Attiya, although not all Shia parties back the draft law.
The dispute comes amid rising tensions between Iraq's once-dominant Sunni minority and newly politically empowered Shia majority that has unleashed a wave of bloodletting.
The influence of neighbouring Shia Iran has concerned the United States and Iraqi Prime Minister Nuri al-Maliki was due to pay his first official visit to Tehran on Monday. But Iraqi and Iranian officials said the trip could be delayed a day or two, and Iraq's envoy to Iran cited "technical reasons".
Washington accuses Iran of giving logistical and financial support to Shia militias in Iraq, something Tehran denies.
The possible break-up of Iraq has been a common theme amid the sectarian strife and unrelenting Sunni insurgency against the US occupation and Maliki's government.
Iraq's parliament faces an October 22 deadline to pass the federalism law that ideally will seek to outline the mechanics of forming federal regions and the relationship between them and the central government, among other issues.
DIVISION OF IRAQ:
Several leaders, notably Abdul-Aziz al-Hakim, the head of the powerful SCIRI party, a partner in the government, have called for a Shia "super-region" of nine provinces to be created in the oil-rich area from south of Baghdad to the Gulf.
Another top leader, radical young cleric Moqtada al-Sadr who draws much of his support from the capital's poor, has voiced reservations about the federal project. He and Hakim held talks in the holy city of Najaf on Sunday.
Some analysts say the failure of the constitution to put a limit on the number of provinces that can form a region is a recipe for disaster and could cleave Iraq into polarised blocs, one Kurdish, one Shia and one Sunni, that would entrench ethnic and religious divisions.
"This law is a step towards the division of Iraq and we want to draw the attention of all Arab and Islamic nations to the dangers of this law ... Federalism is a step toward the division of Iraq," Sunni leader Dulaimi said.
Sunni leaders want a review of the constitution that was promised to win their participation in last December's elections and accuse Shias of being "in a hurry" to pass the law.