MOSUL, Iraq (AFP) -- A violent insurgency in Iraq's second city has been weakened but not defeated, posing key questions for Washington as US troops prepare to withdraw soon, an American commander told AFP Friday.

A military pact signed last year between Baghdad and Washington stipulates that American soldiers pull out of Iraqi cities by June 30, a deadline that gives the chief US commander in northern Nineveh province and its capital Mosul little time to finish off the rebels.

"I tell my guys that tomorrow we have one less day than today," Colonel Gary Volesky told AFP at his quarters in Mosul. "We can't waste a single day."

"We are not sure what will happen after June 30. That is for senior officials to decide," said Volesky, Commander of the 3rd Brigade 1st Cavalry Division, who is in charge of 5,000 troops in northern Iraq.

His comments came as the Iraqi authorities and US military largely ignored the sixth anniversary of the March 20, 2003 invasion that toppled president Saddam Hussein and his totalitarian Baath party regime from power.

"What we cannot afford is a situation where we are not in touch with each other," Volesky said, referring to cooperation between the two armies that sees Iraq take the lead in missions with US support.

"If we're going to move out (of the city) then at least I have to be able to drive in and link up with our Iraqi security force brothers."

The US-led invasion ordered by then President George W. Bush routed Saddam's military, but triggered an Al-Qaeda and Sunni-Arab led rebellion that brought the multi-confessional nation of 29.6 million people to the brink of civil war.

New President Barack Obama last month ordered an end to US combat operations in Iraq by August 2010, ahead of a complete withdrawal the following year.

Since early 2008 the fighting has eased and the sectarian battles that left tens of thousands dead has been brought under control as American and Iraqi forces have exterminated insurgents and rebel militias.

But despite repeated operations in Mosul, it has remained under the influence of insurgents and rebels partly due to a complex Kurd, Sunni and Christian mix, further complicated by tribal loyalties.

Mosul was plunged into violence in 2005 when Al-Qaeda extremists took refuge in the city after being chased out of the capital Baghdad and its neighbouring province of Anbar in western Iraq.

"Anyone I talk to does not believe in the AQI (Al-Qaeda in Iraq) ideology. It's intimidation and it's monetary," said Volesky.

Unemployment rates that have at times hit 80 percent have allowed rebels to continue to lure recruits from financially-strapped and poverty-stricken families with the promise of cash.

Mosul, built as a citadel for the ancient Assyrian empire, is described as the last urban stronghold of Al-Qaeda in Iraq. Volesky admitted the Islamic extremist group has proven a stubborn enemy but he insisted it was not only up to US and Iraqi security forces to fight them.

"We have been killing and capturing insurgents in Mosul for five years," said Volesky.

"The insurgents have the ability to regenerate and we can disrupt them, but people have to decide they are not going to support them."

A grim reminder of Al-Qaeda's ability to strike came in early February when a suicide bomber aboard a car killed Lieutenant Colonel Gary Derby, a 1st Cavalry Division commander, in Mosul.

Nevertheless Volesky remains cautiously optimistic.

Currently on his third tour of Iraq he believes support for Al-Qaeda and other insurgents has waned sharply, with US troops fighting average province-wide attack levels of only seven a day.

He says most of the credit goes to the rapidly-improving Iraqi security forces, of which 25,000 are stationed in Mosul, although as many as one third is on leave at any one time.

"Who are the insurgents attacking? Not us. They are attacking the Iraqi security forces. They now see them as a threat," Volesky said.

In order to keep citizens vested in their city, security sweeps being carried out in problem neighbourhoods are being followed up with services and jobs linked to the local government that will provide more permanent employment.

"Improve the quality of life and that tipping point is out there," Volesky concluded.