Pentagon Chief Ashton Carter said Monday that Washington will deploy 560 additional troops to aid Iraq's fight to retake Mosul from extremists, deepening United States military involvement in the country.
Prime Minister Haider al-Abadi announced on Sunday that Iraqi forces had recaptured the Qayyarah airbase, some 60km south of Mosul, which Isis seized in June 2014.
The extremist group captured Mosul in the summer of 2014.
Carter said he and Abadi discussed the next moves in the war against the jihadists, including Mosul and ways the United States could help beef up security into Baghdad and assist in detecting explosives being smuggled into the capital.
Some US and allied military and intelligence officials warn that, aside from its elite counter terrorism force, the Iraqi military is not ready to take on DAESH militants in Mosul without significant assistance from the Kurdish peshmerga and Shiite militias.
US Defence Secretary Ash Carter has announced the deployment of additional troops to support Iraqi forces in the fight against ISIS.
Carter told reporters that US advisers are prepared to accompany Iraqi battalions in operations, as those units begin the Mosul siege.
Carter, who arrived in Baghdad earlier Monday, announced the USA is sending 560 additional troops to Iraq as part of the stepped-up fight against the "cancer" of ISIL.
"As the campaign shifts toward Mosul, more than 250 miles from the Iraqi capital, the airfield will become a vital springboard for the [Iraqi security forces] offensive into Mosul".
Obama in April allowed us troops to assist Iraqi forces at brigade and battalion levels, where they could operate closer to the battle. "What I'll be discussing with Prime Minister Abadi and our commanders there are the next plays in the campaign, which involve the collapse and control over Mosul", Carter said aboard a military plane.
USA officials said American advisers are already working at brigade level with Iraqi special operations forces, but they have not yet accompanied them on operations.
"We were surprised by how destroyed the base was and how they had done it in an organized way", said Lt. Gen. Abdul Ghani al-Asadi, the commander of Iraqi counterterrorism forces, who planned and participated in the operation to retake the airfield.
Iraq forces recently seized a major airbase near Mosul, marking the completion of the coalition's "first 10 plays" toward defeating Islamic State, said a senior USA defense official.
"The presence of foreign troops is an understandably combustible issue for Iraq; the scars of past battles are, for many Iraqis, equal to current battles against the Islamic State", the report stated.
Carter's short stop in Afghanistan came in the wake of a commitment by North Atlantic Treaty Organisation allies at a summit in Warsaw last week, to keep troop levels stable as they battle a resilient Taliban.
MacFarland said the new forces won't go any closer to the fight than other troops operating out of Makhmour or Taqaddum, a staging base for the battles in Ramadi and Fallujah.
Baghdad is on high alert for attacks after a blast in the central Karada district on July 3 killed more than 300 people.
"There are and have always been people doing temporary things on temporary duty, deployed from other units", Carter said. As many as 186 died in the attack.