Bahrain Mirror- Reuters: The offensive against Islamic State in Mosul could take two more months, and even if the group is defeated there it will still pose a threat to Iraq and the West, the commander of the U.S.-led coalition fighting against it said.

U.S. Lieutenant-General Stephen Townsend said Iraqi forces had made significant progress since the ultra-hardline militants rampaged through the north of the country in 2014 and then declared a caliphate that also straddled parts of Syria.

"I think they are going to be working on Mosul for a number of weeks more, maybe a couple of months more probably," Townsend told Reuters in an interview aboard the French aircraft carrier Charles de Gaulle during a visit with senior military officers.

The U.S.-led Operation Inherent Resolve coalition, which includes military forces from a range of Western and Arab countries, has been bombing Islamic State positions in both Syria and Iraq since 2014.

It is now providing air support and some ground assistance to the Iraqi assault on Mosul in Iraq, and working with Kurdish and Arab fighters who have made advances against Islamic State in Syria.

The Mosul assault, involving a 100,000-strong ground force of Iraqi government troops, members of the autonomous Kurdish security forces and mainly Shi'ite militiamen, is the biggest battle in Iraq since the U.S.-led invasion of 2003. The pro-government forces have captured around a quarter of the city so far, but fighting has been slowed by the presence of an estimated 1 million civilians.

Townsend said victory in Mosul would not eradicate Islamic State: "I think we are not done when Mosul is over. We are still not done in Iraq. We are still about a third of the Euphrates River valley up to the Syrian border that has to be cleared," he said.

"Our partners have to go from Mosul out to the Syrian border in the West and reestablish control of their border. There is still a tough fight ahead even after Mosul."

While sooner or later Islamic State fighters would "realise they are going to lose their physical caliphate", he predicted they would adapt their tactics and remain a threat, even after all their territory was reclaimed.

"They will have to change what they are doing and become more of a virtual caliphate, I think. Devolve into an insurgency over time. In Iraq and Syria," he said.

"They will certainly continue to plot and plan and attempt attacks on the West as long as they exist. In my view the best way we can reduce the threat of external attacks on France or the United States or the West is to kick them out of Mosul, and to kick them out of Raqqa and to chase them into the desert."

Iraq's recent history, in which Islamic State formed from the remnants of al Qaeda fighters subdued during eight years of U.S. occupation, shows that defeating one militant group can lead to the emergence of a graver danger. Townsend said this meant coalition countries would have to keep a presence in Iraq.

"I don't have a crystal ball. I can't predict the future. I do know that they have shown the ability to come back. Al Qaeda in Iraq gave birth to ISIS, Daesh," said Townsend, using two acronyms to refer to Islamic State, also known as ISIL.

"SUSTAINABLE PRESENCE"

"What we have to do is we have got to play this differently so that ISIS doesn't give birth to the next extremist group that takes over Iraq," said Townsend. "We need to make sure we have a sustainable presence and a partnership in Iraq, the coalition into the future."

His view was echoed by French Admiral Olivier Lebas, one of the officers he met aboard the carrier: "It is really important to stay as long as necessary to make sure that we eradicate ISIS. It is a very important phase," Lebas told Reuters.

Townsend said the campaign against Islamic State in its Syrian headquarters of Raqqa would be more complex than the Mosul operation and would take more time, in part because the coalition is relying on a smaller local fighting force of Syrian Kurdish and Arab fighters rather than the big Iraqi army.

At the moment they are conducting an approach march, said Townsend. The aim is to eventually isolate Raqqa, lay siege to it and then attack, he added.

"Mosul is hard. It's a big, complex city. The enemy has had two years to dig in and prepare their defences. Mosul would challenge the French army. It would challenge the United States army. It's really tough," said Townsend.

"But there is a government in Iraq and there is an army fighting to take back Mosul. In Syria, we are trying to fight Daesh with local partners, adjacent to a civil war, with all sorts of outside influences."

Arabic Version