On Monday, visiting US Defence Secretary Ash Carter said Washington will send 560 more troops to Iraq to help battle IS.
"So the idea is that these new US forces would be used to secure the airfield and essentially get it up and running as a logistics hub that would support ongoing operations by Iraqi security forces", White House press secretary Josh Earnest said at the July 11 press briefing.
Some U.S. and allied military and intelligence officials warn that aside from its elite counter terrorism force, the Iraqi military is not ready to take on Islamic State militants in Mosul without significant assistance from the Kurdish peshmerga and Shi'ite militias.
The latest deployment will bring the number of U.S. personnel in Iraq to more than 4,650, the BBC reported.
The advance to the south of Mosul brought the village of Ajhala back under government control to the north of the Qayara Air Base, which was retaken by government forces on July 9.
A suicide vehicle bomber hit a police checkpoint on Wednesday, killing at least eight people in a Baghdad district that was struck by a deadly attack the day before, Iraqi officials said.
There is a sizable percentage of Iraqis, the report noted, who believe "the U.S. and other foreign powers are in some way supporting the Islamic State as a disruptive wedge against a stable Iraq".
Abadi has pledged to retake Mosul by the end of the year.
Ashton Carton made the comments as he made an unnannounced visit to the Iraqi capital
A senior United States defense official said Qayara air base would be "an important location for our advisers, for our fire support, working closely with the Iraqis and being closer to the fight".
Iraqi forces recently retook both cities.
Iraqi government forces deployed in most of Baghdad on Tuesday, closing off main roads and causing traffic chaos.
IS has increasingly resorted to ad hoc attacks, including a bombing in the Iraqi capital last week that left almost 300 people dead - the most lethal bombing of its kind since the 2003 US-led invasion that ousted Saddam Hussein.
US forces have already visited Qayara to check on its condition, and advisors can offer specialised engineering support in Mosul, US officials said.
The Islamic State, also known as Daesh in Arabic, has controlled Iraq's second largest city of Mosul for the past two years.
"It's something Americans should be vigilant about", he added, saying citizens should be "tracking the nature of America's involvement here" since "it's not going away".