Fresh advance in east Mosul to begin within days

Iraqi forces will resume their push against ISIS inside Mosul in the coming days, a U.S. battlefield commander said, in a new phase of the two-month-old operation that will see American troops deployed closer to the front line in the city.

The battle for Mosul, involving 100,000 Iraqi troops, members of the Kurdish security forces and Shiite militiamen, is the biggest ground operation in Iraq since the U.S.-led invasion of 2003. The upcoming phase appears likely to give American troops their biggest combat role since they fulfilled President Barack Obama's pledge to withdraw from Iraq in 2011.

Elite Iraqi soldiers have retaken a quarter of Mosul, the militants' last major stronghold in Iraq, but their advance has been slow and punishing. They entered a planned "operational refit" this month, the first significant pause of the campaign.

A heavily armored unit of several thousand federal police was redeployed from the southern outskirts two weeks ago to reinforce the eastern front after army units advised by the Americans suffered heavy losses in an ISIS counterattack.

U.S. advisers, part of an international coalition that has conducted thousands of airstrikes and trained tens of thousands of Iraqi ground troops, will work directly with those forces and an elite Interior Ministry strike force.

"Right now we're staging really for the next phase of the attack as we start the penetration into the interior of east Mosul," Lieutenant Colonel Stuart James, commander of a combat arms battalion assisting Iraqi security forces on the southeastern front, said in a Reuters interview late on Sunday.

"So right now, positioning forces and positioning men and equipment into the interior of east Mosul ... it's going to happen in the next several days."

That will put U.S. troops inside of Mosul proper and at greater risk, though James said the danger level was still characterized as "moderate." Three U.S. servicemen have been killed in northern Iraq in the past 15 months.

James, speaking from an austere outpost east of Mosul where several hundred U.S. troops are stationed, said the pace of the upcoming phase on the eastern side would depend on resistance from ISIS.

"If we achieve great success on the first day and we gain momentum, then it may go very quickly. If Daesh fights very hard the first day and we run into a roadblock and we have to go back and go OK that was not the correct point of penetration, it may take longer," he said.