The U.S. was preparing to send 600 more troops to Iraq for the long-awaited offensive to drive the Islamic State from the stronghold of northwestern Mosul, where ISIS fighters were expected to use mustard gas to blunt the attack, Pentagon officials said Wednesday.
The official announcement was expected to come later in the day the additional troops, who were expected to operate as trainers and enablers mostly out of the logistics hub for the offensive at the Qayyarah West airfield about 40 miles southeast of Mosul.
Earlier this week, Navy Capt. Jeff Davis, a Pentagon spokesman said that ISIS was "dead set" on using chemical weapons to defend Mosul. Last week, a shell fired by ISIS near U.S. troops in Qayyarah was initially thought to contain blistering mustard gas but later tests showed that it was not a chemical weapon.
Air Force Col. John Dorrian, a spokesman for Combined Joint Task Force-Operation Inherent Resolve, also said that ISIS was attempting to turn Mosul into a "living hell" for the attacking force by setting out extensive fields of improvised explosive devices and even filling trenches with oil.
The troops would be in addition to the 4,647 currently authorized for Iraq by President Obama and were requested by Iraqi Prime Minister Haider al-Abadi.
In a statement, Abadi said "American President Barack Obama was consulted on a request from the Iraqi government for a final increase in the number of trainers and advisers under the umbrella of the international coalition in Iraq," Reuters reported.
"In anticipation of the Mosul fight, the United States and the government of Iraq have agreed that additional U.S. and coalition capabilities could help accelerate the campaign at this critical phase," Defense Secretary Ashton Carter said.
Carter, on a four-state swing to promote the modernization of nuclear forces, said in a statement that he and Joint Chiefs Chairman Gen. Joseph Dunford first requested the additional troops. "With the support and approval of Prime Minister Abadi, President Obama has authorized approximately 600 additional U.S. troops to further enable Iraqi forces," he said.
The troops will be involved in logistics and maintenance support, and also provide "train, advise and assist teams for Iraqi Security Forces and Kurdish Peshmerga" fighters for the Mosul push, Carter said.
Army Lt. Gen. Stephen Townsend, commander of the task force, already has authority to place U.S. advisers with the attacking force at the battalion level, but it was unclear whether Townsend would exercise that authority.
The timeline for the Mosul offensive has not been disclosed, although some recent reports have suggested that it could begin as early as next month. Carter told reporters traveling with him that the campaign would intensify in the coming weeks. "We've said all along, whenever we see opportunities to accelerate the campaign, we want to seize them," he said.
U.S. actions in support of the planned offensive have been intensifying in recent weeks. The U.S. has moved the truck-mobile HIMARS rocket artillery system into the Qayyarah area, along with the .155mm M777 howitzers of the 2nd Brigade Combat Team, 101st Airborne Division.
In addition, the Iraqis have been told that AH-64 Apache gunships will be available to support the Mosul attack if requested. The Apaches were also available for the successful retaking of Fallujah west of Baghdad earlier this year, but the Iraqis chose not to ask for them.
Editor's Note: This story has been updated to correct a spokesman's service.
-- Richard Sisk can be reached at Richard.Sisk@Military.com.