"We have to say that if a federation is established in Iraq, particularly a federation based on ethnic roots, the future of Iraq will be very difficult and very bloody," deputy chief of staff Ilker Basbug told reporters.

His remarks echoed an earlier warning by Ankara, which fears that the Iraqi Kurds, strong proponents of a federation, could expand their self-rule in northern Iraq, setting an example for their restive cousins in neighboring Turkey.

"But if the Iraqi people decide on a federal structure, it would be better to do this on a geographical basis rather than on ethnic foundations," Basbug said.

He stressed that a federal system based on the current 18 provinces in Iraq would be "the most suitable" solution.

The general also said the natural riches of Iraq should not be dominated by certain groups -- an apparent reference to Kurdish demands to extend their self-rule from the three northern provinces they currently run to nearby oil-rich regions such as Kirkuk.

Ankara suspects the Iraqi Kurds of plotting to break away from Baghdad, a prospect that could also spark instability on Iraq's borders with Iran and Syria, which also have Kurdish communities.

The Turkish military's warning came as a senior Iraqi Kurdish official, Barham Saleh of the Patriotic Union of Kurdistan (PUK), sought to dispel Ankara's fears during a visit to the Turkish capital.

"We are committed to a federal democratic Iraq. This will ensure the integrity of Iraq and the protection of the rights of its communities," Saleh said after talks with Turkish diplomats, Anatolia news agency reported.

"The division of Iraq on the basis of sectarian, religious and ethnic elements is not the direction in which we will be moving," he said.

Turkey has urged the United States not to favor the Iraqi Kurds, their war-time ally, in the shaping of post-war Iraq.

In another appeal, General Basbug called on Washington to make good on its promises to take action against an estimated 5,000 rebels from the Kurdistan Workers' Party (PKK), an outlawed Turkish Kurd group, who found refuge in mountainous northern Iraq prior to the US invasion of the country.

"The current situation does not meet our expectations... It has become difficult for us to wait more. We think the US has to start certain military actions in a short time against this terrorist organization," he said.

The PKK, which has waged a bloody 15-year campaign for self-rule in southeast Turkey, is considered a terrorist organization by both Ankara and Washington.

Basbug said the PKK recently stepped up activities both in Turkey and Iraq to transform itself into a political organization.

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