Erbil, northern Iraq, 15 November 2004 - American Marines from Falluja and Iraqi National Guard (ING) battalions from Kurdish autonomous region have deployed to Mosul to reinforce American and ING units based in the city, Kurdish and American military officials said. They said the local security forces had lost control of much of Mosul, Iraq's third largest city with an estimated population of 1.8 million Arabs, Kurds, Turcomen and Assyrian Christians.

US troops and Iraqi security forces were fighting to retake a police station overrun by insurgents in the northern city of Mosul, a US military spokeswoman said on Sunday. Two US soldiers were also wounded in sporadic fighting in the nearby town of Tal Afar, where insurgents had attacked a police academy with small arms, she said. Last week, insurgents stormed and looted at least nine police stations in Mosul, Iraq's third largest city, stealing weapons, flak jackets and police vehicles.

US Brigadier General Carter Ham, in charge of security in the north, said on Saturday that all the city's 33 police stations had been secured and the city of two million was returning to calm, although he expected further attacks.

Mosul tipped into chaos on Wednesday and Thursday when groups of up to 50 militants took over some neighbourhoods, paraded through the city centre brandishing their weapons and chased away local police.

"Mosul was about to be lost," Brigadier Anwar Dolan, commander of the ING brigade in Suleimania in the Kurdish-controlled north, said. "So, the Iraqi Defence Minister asked for forces from Suleimania, Dihouk and Erbil." Reports from inside Mosul indicated that insurgents, joined by local policemen, were patrolling the streets to demonstrate their power in neighbourhoods of the city's Arab majority. Meanwhile, outside the city, the American-ING forces were mobilising for what some military officials promise would be another Falluja-type assault.

"We will be moving in the next day or so in Mosul to restore the rule of law," announced Iraqi interim prime minister Iyad Allawi. An Iraqi journalist in Mosul reported that ING troops have retaken two of the six police stations controlled by the insurgents. Insurgents and American-ING battalions were each demonstrating their control of different parts of Mosul in advance of what most observers believe will be a major battle for the city.

Brigadier Dolan, a veteran Kurdish fighter, blamed Iraqi government forces based in Mosul for yielding to the insurgents. "I am sure the [Mosul ING] brigade is not professional. Suleimania and Erbil [Kurdish ING battle groups sent to Mosul] are veteran Peshmergas." Peshmergas are Kurdish fighters, some of whom were recently absorbed into the ING. Technically under the Iraqi defence ministry in Baghdad, they are based in Peshmerga encampments and answer to Kurdistan's two political leaders - Massoud Barzani and Jalal Talabani. Iraq's deputy prime minister, the Kurdish politician Barham Saleh, said he feared that deploying Kurd-only units against Arab forces in Mosul could lead to an all-out Arab-Kurdish war in Iraq.

Most of Mosul's 400,000 Kurds - nearly a quarter of the population - live on the east bank of the River Tigris. Insurgents attempted, and failed, to gain a foothold on the Kurdish side of the river on Thursday. So far, the Kurds have kept them out of their areas. However, some Kurds have left Mosul - fearing further attacks by the mainly Arab insurgents. The insurgents seized large numbers of police weapons on Thursday and Friday, and the US forces responded with aerial bombardment.

"I personally gave clear instructions to my soldiers to be careful," Brigadier Dolan said, "not to send the message that this is a fight between Kurds and Arabs. There is a danger that the terrorists are trying to create a war between us and the Arabs."

With more than 30,000 men under arms, the Kurdish autonomous region has the strongest indigenous force in Iraq. However, deploying them in Arab areas could increase Arab suspicions of the Kurds and lead to attacks on the estimated two million Kurds living in non-Kurdish cities like Baghdad and Mosul. Kurds have already suffered at the hands of insurgents this year, with many murdered in Baghdad and elsewhere.

The US military said that thirty of its soldiers had died in Fallujah since the battle began there on 8 November, while another twenty were killed elsewhere in Iraq during the same period - bringing the total to fifty American dead in one week. Because Mosul is a much larger city than Falluja and its Arab populace is showing sympathy for the insurgents, the fighting there could be more bloody than in Fallujah. Mosul has a history of ethnic conflict dating back to 1925, when Britain included Mosul province in the new state of Iraq in 1925 - over Turkish and Kurdish objections. About 24,000 officers in Saddam Hussein's army came from Mosul.

The surge in violence coincided with the US military's full-scale offensive against an estimated 2,000-3,000 insurgents - foreign fighters, Sunni Muslim nationalists and loyalists to the former regime - holed up in Falluja, west of Baghdad.

Military officials say many of the militants there fled before the attack, and that there has been an increase in violence across towns and cities throughout the Sunni Muslim belt of the country since.

Bowman said Mosul remained "relatively calm" on Sunday despite the attack on the police station, and said its governor remained confident the city was under his control.

Following the attacks last week, the Iraqi government fired Mosul's police chief and sent national guard reinforcements to boost the security force presence on the streets.

A battalion sent to help out in Falluja, was deployed back to Mosul last week to help reestablish control in the city.

"We hated the Baath, not the Arabs," said Brigadier Dolan. "If we deploy, it is to fight terrorists - not Arabs." Whether the Arabs see their old Kurdish enemies in those terms is one question the battle for Mosul will answer.