In Kirkuk, the crown jewel of the 300-mile strip of disputed territories, Arab politicians announced over the weekend the creation of a political group that includes Sunni leaders who gained prominence in 2006 and 2007 when, with financial backing from the United States, they took up arms against the group al-Qaeda in Iraq in the western part of the country.
The Kurds, meanwhile, have been aggressively collecting signatures in the oil-rich city for a nonbinding petition with which they hope to demonstrate that the majority of Kirkuk's residents want the city annexed to the autonomous Kurdish regional government.
The much-anticipated release of the U.N. reports, expected this month, could open a new chapter in the visceral, decades-long dispute between Arabs and Kurds over Kirkuk and other key cities and villages in northern Iraq.
Many of the urban areas in the disputed territories were predominantly Kurdish until the 1970s, when Saddam Hussein razed hundreds of Kurdish villages, displacing thousands of people. He also provided incentives for Arabs in southern Iraq to move north.
Since the U.S. invasion of Iraq in 2003, the Kurdish regional government -- which operates much like a sovereign nation and has its own armed force -- has worked aggressively to restore its influence in several areas that were formerly under Kurdish control. It has spent millions on social services and deployed its militia, the pesh merga, to parts of Nineveh, Diyala and Kirkuk, the three provinces that border the autonomous regional government.
Prime Minister Nouri al-Maliki and other Arab leaders have accused Kurds of encroaching in areas that are under nominal control of the Baghdad government. Maliki in recent months deployed troops loyal to the central government to stem the influence of the Kurdish regional government.
The tension over Kirkuk and other disputed areas, which some Iraqi and U.S. officials believe could escalate into armed conflict, prompted the U.S. military in January to increase its troop level in Kirkuk from a battalion, roughly 900 troops, to a combat brigade of about 3,200 soldiers.
"The threat of civil war remains real, and this threat should not be minimized," said W. Andrew Terrill, a national security professor at the U.S. Army War College's Strategic Studies Institute. "Kirkuk is often compared to Jerusalem, where different groups have exceptionally strong emotional attachments and the claims of rival groups are rarely seen as valid."
The debate over control is linked to the still-unresolved question of how Iraq will distribute its oil wealth. Complicating matters, it is coming to a head in a politically charged year during which missteps by candidates over their position on Kirkuk could amount to political suicide.
U.N. officials this week briefed Maliki, a Shiite; President Jalal Talabani, a Kurd; and other senior Iraqi leaders on the reports. U.N. officials have refrained from discussing the reports publicly.
Iraqi analysts and politicians in northern Iraq who have discussed the issue with U.N. officials in recent weeks said in interviews that they expect the organization will outline a scenario by which Kirkuk could be administered jointly by the central government in Baghdad and the Kurdish regional government. Elsewhere, based on an analysis of the region's history, demographics and the outcome of the recent provincial election, the United Nations is expected to suggest that certain districts ought to be administered by the Kurdish regional government.
Hussein Ali Salih al-Juburi, a senior Arab political leader in Kirkuk, said local politicians decided to form the Iraqi Kirkuk Bloc to "strengthen the Arabs' position" on what he called "Kurdish intransigence." He said the group intends to deploy the paramilitary groups known as Awakening councils, or Sons of Iraq, to fight insurgent groups in villages in northern Iraq.
Kurdish politicians in Kirkuk say they won't accept any deal that prevents the Kurdish regional government from annexing the city.
"We shall accept a solution for Kirkuk worked out by the parties inside the city and oppose any solution imported from outside parties that are enemies to the Kurdish people's experiment," said Najat Hassan Karim, a senior Kurdish politician.
The security situation in Kirkuk, which saw little violence in the years after the invasion, has deteriorated in recent months. A suicide bomber killed 50 people at a restaurant in December. On Wednesday, another suicide bomber killed 11. Iraqi and U.S. officials fear insurgent groups could seize on the political and military stalemates to make a comeback in the region.
Tension between armed forces loyal to the Iraqi government and the Kurdish regional government nearly led to a shootout last fall in Khanaqin, a town in Diyala province. Conflict was narrowly averted by U.S. soldiers. Talib Mohamed Hassan, a Kurdish politician in Khanaqin, recently took visiting journalists to one of the villages razed during the 1970s. For Kurds, he said, these areas are hallowed ground.
"We don't call these disputed areas," he said, walking through chunks of cement where homes once stood. "We call these areas that were sliced off."
In Nineveh province, the recent provincial election left the council, formerly controlled by Kurds, solidly in the hands of Arabs. When the new council was seated this week, the Kurds walked out, saying they were not given a fair number of key positions.
Raid Jahid Fahmi, the leader of a committee appointed to ease tensions over Kirkuk, said a lasting solution seems unlikely in a politically charged year. National elections are expected in the winter.
"It's better to have a good solution in three years than a shaky one in one year," Fahmi said. "A durable solution might take some time. It is now proven that setting deadlines for complex political issues is not a good thing."
American officials fear the consequences of leaving the dispute unresolved as the U.S. military withdraws, and they have urged both sides to take the U.N. reports seriously.
"We need facilitators with teeth," a senior Iraqi official said, speaking on the condition of anonymity to offer his candid assessment. "The U.N. has no teeth. Keeping this herd of cats together without American leadership won't happen."
But the United States has avoided taking sides.
"The United States cannot forcefully inject itself into this conflict without creating a massive number of new enemies in Iraq and worldwide," said Terrill, the professor. "I think that the United States has to contain the violence and encourage dialogue, but I do not think we can go beyond that without making things worse."