Iraqi Prime Minister Nuri al-Maliki has already bolstered the central government's power through security operations in Baghdad and the south of the country, and is now turning his attention to northern regions where tensions are high between Sunni Arabs, Turkomans, and Kurds.
But as Maliki seeks to extend his control over hotspots like Mosul and Kirkuk, the Kurds are warning him not to go too far.
The two main Kurdish political parties are key members of the Iraqi political establishment in Baghdad, with one of the parties' leaders, Jalal Talabani of the Patriotic Union of Kurdistan (PUK), currently serving as Iraq's president.
But the Kurdish parties are at odds with the central government when it comes to any threat to self-rule in the three majority-Kurdish provinces they control.
They also differ with Baghdad over how much of the mixed Kurdish-Arab-Turkoman provinces that border the Kurdish autonomous region should eventually be brought into it.
Particularly sensitive is the oil-rich city of Kirkuk, which many Kurds regard as their natural future political and economic capital. So, too, are disputed areas around the cities of Mosul near the Turkish border, and Khanaqin on the Iranian border.
Until recently, the Kurdish parties were the dominant power in these areas due to two factors. First, their fighters, the peshmerga, swept in as U.S. forces toppled Saddam Hussein and then stayed on as units of the new Iraqi Army. Second, the Sunni Arab boycott of the 2005 provincial elections assured there was only weak political opposition.
But now the Sunni Arabs are reasserting their claims in the mixed population areas. They returned in force to the provincial polls this year and were the biggest winner in Mosul. In Kirkuk, where the January poll was waived for fear of violence, Arab and Turkoman militias patrol their own neighborhoods even if the Kurds dominate the city's tripartite government.
The situation makes Maliki's efforts to build on his security successes in the south and Baghdad, by turning his attention northward, seem both urgent and risky.
So far, he has proceeded cautiously. He has focused on quietly changing the composition of the Iraqi Army forces in the disputed regions in an effort to reduce the peshmerga presence.
In Kirkuk, that has meant replacing the Iraqi Army's 4th Division with the 12th Division, but the move has drawn fierce protests from the Kurdish side.
Safin Dizayi, head of international relations for the Kurdish Democratic Party (KDP), the other of the two main Kurdish parties, says the troop rotation is bringing in almost exclusively Arab soldiers.
"Prior to the arrival of this [12th] division, there was the 4th Division in the Kirkuk region. And orders came for the 4th Division to be removed, which actually had a mixed composition of Kurds and non-Kurds, and it was sent to another part of the country and the 12th Division was brought in its place," Dizayee says. "The new division, the 12th Division, is mainly comprised of Arab officers, staff officers and high-ranking officers, right down to foot soldiers."
Kurdish officials also charge Maliki with moving away Kurdish officers in the two Iraqi Army divisions in Ninevah province, whose capital city is Mosul.
Dizayee also says such moves sidestep long-standing efforts in Baghdad to negotiate the status of the disputed areas.
"There are certain areas which under the constitution, Article 140, require a legal settlement [because] they are disputed areas between Kurdistan and the rest of Iraq," Dizayi says. "We feel that so long as these regions remain in dispute, any form of military movement would probably complicate the situation further and create unnecessary concern."Replacing Peshmerga
The Kurds have counted on a constitutionally mandated referendum, including in Kirkuk, to determine which areas join the Kurdish autonomous region. But the wrangling in Baghdad has gone on so long that the date for the referendum expired a year ago and, in a sign of the growing impasse, no new date has been set.
Still, if Maliki's effort to change the military composition in the disputed areas dismays Kurdish leaders, it has been hailed by local Sunni Arab parties.
Mas'ud Barzani (right), the president of the Kurdish self-rule region, has publicly suggested Maliki is drifting toward authoritarian rule.
"We needed to change the army because previously the soldiers in Mosul were in Iraqi Army uniform but they were from the Kurdish militia -- and when I say Kurdish, I mean from the two parties [KDP and PUK]," Izzedin al-Dora, a deputy to the national parliament from Mosul, says. "So we asked Baghdad to change the army, they tried more than once, and now they have changed about 70 percent so far. We want more."
Dora represents the party Al-Hadba (the Arabic name for Mosul), which took 49 percent of the vote in the Ninevah provincial election.
He says the remaining 30 percent of change he wants to see includes removing peshmerga units of the Iraqi army that continue to control areas outside Mosul, particularly along the border with the Kurdish autonomous region.
"So far, outside of Mosul, in some places like Al-Hamdaniyeh, like Shaikhan, where the [Kurdish] parties exercise power, the Kurdish forces are still there," Dora says.
The Al-Hadba party is headed by Athil Najafi, the scion of an old Mosul family that breeds Arabian horses and used to supply them to Saddam Hussein's sons, Uday and Qusai. It is regarded by the Kurds as not only fiercely Sunni Arab, but also as having ties to former Ba'athists. Threat Of Violence?
Al-Hadba, in turn, accuses the Kurdish forces of arbitrary arrest and torture of opponents.
So far, the efforts to change the military structure in the disputed areas have not led to open fighting.
"Up to now, I can say, 'no,'" Dora says. "Maybe sometimes it happens, but not openly and we have not heard or seen any of that -- for now."
But Kurdish leaders says Sunni Arab gunmen in Ninevah have killed some 2,000 Kurds and turned another 127,000 into refugees over the past six years. Most of the Kurds living west of the Tigris, the river that divides Mosul, have fled.
That means that in Mosul -- Iraq's third-largest city -- the Kurds are fighting a rearguard action to remain in the majority Arab city. By contrast, the Kurds in Kirkuk are waging a battle to retain control of a city they hope to one day see as their capital.
How much further Maliki can go in changing the military structure in the north while still preserving his frequent alliance with the Kurds in Iraqi national politics is now a major question.
The war of words between the two sides keeps growing. Mas'ud Barzani, the president of the Kurdistan region, has publicly suggested Maliki is drifting toward authoritarian rule.
That is not the first time someone has leveled that charge at Maliki, the Shi'ite Arab politician whose popular "State of Law" operations in Baghdad and Basra have bolstered his drive for a strong central government. But in the past the charge more often has been leveled by Iraq's Sunni Arabs, or rival Shi'ite Arab parties, rather than by the Kurds.RFE/RL's Iraq Service contributed to this report