Turkish Foreign Minister Abdullah Gul has warned this Sunday's elections in Iraq could be flawed due to Kurdish attempts to increase the number of voters in the oil rich northern Iraqi city of Kirkuk, Turkish private NTV reported onMonday.

A letter dated January 19 to United Nations Secretary General Kofi Annan from Foreign Minister Abdullah Gul outlined Ankara's concerns over Kirkuk, saying that Kurdish groups in northern Iraq were making artificial population changes in the region.

Without naming any major Kurdish factions, Gul said that Kurds were being moved to Kirkuk ahead of the poll and that was threatening stability.

Gul also stressed that the participation of all the groups in Iraq must be encouraged.

"The exclusion of certain segments of the Iraqi society in the election will cause serious problems in the future of Iraq," said Gul.

Meanwhile, Ankara is trying to block the participation of Kurdistan Democratic Solution Party and Iraq Democratic Renewal Party in the upcoming Iraqi elections because of their alleged association with the outlawed Kurdish Workers Party (PKK).

"The participation of these parties in the elections would not imply that they are legitimate parties, eligible to participate. The Iraqi government demanded proofs that these parties are associated with the PKK. The Iraqi government wants to portray an image that it is not meddling in the works of the Independent Election Commission," said a Turkish diplomat.

The PKK, which wants to establish an independent Kurdish state in southeast Turkey and northern Iraq, launched an armed campaign against the Turkish government in 1984, claiming 30,000 lives, mostly Kurds.

Fighting subdued significantly in 1999 when Turkey captured PKK commander Abdullah Ocalan, but the PKK called off its unilateral ceasefire in 2004, threatening to wreck the southeast's fragile peace.

The Turkish government refuses to negotiate with the PKK, which it deems as a terrorist organization.