"Turkey is pressuring us to narrow our differences with the Kurds" over Kirkuk, said Saadeddin Arkij, head of Iraq's Turkmen Front, the largest political party representing the country's Turkmen minority.

Erdogan arrives on Monday for a two-day visit to Iraq, during which he will also visit the Kurdish regional capital of Arbil, becoming the first Turkish prime minister to do so.

"One of the aims of the visit is to try and narrow the gap between Turkmen and Kurds, but it is not yet certain what measures he will take," Arkij said, adding that Turkmen politicians and MPs had been invited to visit the Turkish embassy in Baghdad during Erdogan's trip.

The principal dispute between the Kurds and Turkmen is over the oil hub of Kirkuk, which has a mixed Arab, Kurdish and Turkmen population and is claimed by all three groups.

The governor of Kirkuk province and the head of its provincial council, who officially report to the Arab-led central government in Baghdad, quit earlier this month, complaining it was impossible to govern because of the competing claims.

Kirkuk province is one of a number of territories that the Kurds want to incorporate in their autonomous region in the north.

The fight against the Kurdistan Workers' Party (PKK), which has rear-bases in the border area, will also be discussed during Erdogan's visit, the sources in Ankara said.

Turkey has repeatedly accused the Iraqi Kurds of turning a blind eye to activity within Iraq by the PKK but their leaders have been careful no to anger the larger neighbour.

Turkish firms provide some 80 percent of the region's food and clothes, and trade rose 30 percent between 2008 and 2009. Overall Iraq-Turkish trade, much of which passes through Kurdistan, amounted to seven billion dollars in 2009.

Foreign Minister Ahmet Davutoglu and a delegation of businessmen are to accompany Erdogan.

The PKK, which is viewed as a terrorist group by Ankara and much of the international community, took up arms against Ankara in 1984 for self-rule in Turkey's Kurdish-populated southeast, sparking a conflict that has claimed some 45,000 lives.

Kurdish populations live in northeastern Syria and western Iran as well as southeastern Turkey and northern Iraq.