Speaking hours after thousands of rebels poured into Kirkuk on day 22 of the US-led war on Iraq, Turkish Foreign Minister Abdullah Gul said US Secretary of State Colin Powell had guaranteed that they would be driven out.

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

Pentagon officials said later that a battalion of US army paratroopers had moved into Kirkuk after its capture by the rebels drew warnings from Turkey that a Kurdish occupation was unacceptable.

A spokesman for rebel Patriotic Union of Kurdistan (PUK), meanwhile, told AFP that their fighters would be pulling out anyway on Friday.

Turkey has repeatedly threatened to intervene militarily in northern Iraq if Kurdish forces seized Kirkuk or Mosul, home to some of Iraq's largest oilfields.

Ankara fears that oil revenues could strengthen an Iraqi Kurdish bid for independence, a prospect that could rekindle a separatist Kurdish rebellion in adjoining southeast Turkey.

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

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 pledge, 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 but had invited Ankara to send military officials to monitor the situation on the ground.

Kurds deny they are seeking independence for 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.

In Washington, White House spokesman Ari Fleischer said that "American forces will be in control of Kirkuk."

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.

Turkmen -- an ethnic Turkish minority in Iraq backed by Ankara -- also claim Kirkuk and Mosul as their own.

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