Turkey has repeatedly threatened to intervene militarily in northern Iraq if Kurdish forces seized Kirkuk or Mosul, the two largest towns in the region.

The towns control some of Iraq's richest oilfields and the revenue could strengthen an Iraqi Kurdish bid for independence, a prospect that could set an example to their restive cousins in Turkey..

The United States is staunchly opposed to any intervention in the region by Ankara, fearing clashes between Turkish troops and Iraqi Kurds.

Speaking hours after Kurdish forces poured into Kirkuk on day 22 of the US-led war on Iraq, Turkey's Foreign Minister Gul said he had received guarantees from US Secretary of State Colin Powell to drive them out.

"He said the 173rd paratroopers brigade will go to Kirkuk in a few hours and force out those who have entered," Gul said.

A Turkish government official later said that a first group of US troops had arrived in the city Thursday evening and a second was on its way.

Gul appeared relieved by the US pledges, but said Turkey -- a key US ally and the only NATO member to border Iraq -- would closely monitor developments and act if necessary.

"In the face of the (US) guarantees, there is no need to be uneasy... First of all, let us remain optimistic, but we have contingency plans," he said.

He added that Washington had rejected a Turkish offer of military help in case there were not enough US soldiers in the area.

Ankara will however deploy military observers in northern Iraq to ensure Kurdish forces leave, he said.

"We will have military observers there... They (the United States) made the offer and we accepted it," Gul said.

Such a move is likely to draw the ire of Iraqi Kurds who strongly oppose any Turkish military presence in the area.

Kurds deny that they are seeking independence in their mountainous enclave -- which has been outside Baghdad's control since the 1991 Gulf War -- but Turkey remains deeply suspicious of their political ambitions.

A senior Turkish diplomat said Ankara would not agree to any permanant Kurdish control over Kirkuk.

"It would be unacceptable if they (the Kurds) entered the town to take control and set up an administration," said the diplomat, who requested anonymity.

Iraqi Kurds lay claim to both Kirkuk and Mosul saying they were in the majority there before the cities were taken over by Arabs under the regime of Iraqi President Saddam Hussein.

Thousands of Kurdish exiles began rushing back to Kirkuk after its fall on Thursday, some in a bid to reclaim property and some to see relatives.

But Gul insisted that Turkey will not allow Kurdish refugees to change the demographic make-up of Mosul and Kirkuk, where residents Thursday pulled down a large statue of Saddam and burned a giant portrait of the Iraqi president.

"We will not authorise either people with weapons or without weapons, who could try to destroy the demography and the structure of these cities," he said.

Turkmens -- an Iraqi ethnic Turkish minority backed by Ankara -- also claim Kirkuk and Mosul as their own.

They say they are the third largest ethnic group in northern Iraq after the Arabs and the Kurds, and estimate their own numbers at three million.

Kurds dismiss Turkmen claims -- saying their community is no larger than half a million -- and they consider Kirkuk as their own prospective capital in a federal Iraq.

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