Shafaq News/ Iraqi pilots said that the pricey F-16 fighter program is collapsing, due to poor maintenance services, after the withdrawal of American experts from the Balad air base, according to a Fox News report published on Wednesday.

Nine years ago, just before the Obama administration pulled the plug on a troop presence in Iraq, Baghdad signed a landmark $4.3 billion, U.S.-backed Lockheed Martin deal to bolster its burgeoning air force with its very own fleet of F-16 fighter jets. The first batch arrived three years later, under the guise that the force would stand on its own two feet, Fox News reported.

But billions of dollars and almost a decade later, some Iraqi pilots tell Fox News that there is little left of their investment and they fear few pilots are combat-ready to take on another ISIS wave or emerging threat.

According to two Iraqi Air Force pilots, who spoke on the condition of anonymity as they were not authorized to speak on the record, issues have emerged over the past months.

"The issue is Lockheed withdrew its employees. However, all these planes [F-16s] need to be serviced and supervised," one source said. "But because of a lack of parts, the Iraqi defense ministry started making its own parts and things, which is not allowed and effectively voids the warranty on them. In one case, a tool was left inside one of the engines."

The Iraqi pilot claimed that "most planes are now grounded because they [air force personnel] don't know what they are doing re the upkeeping, which in turn means that the Iraqi pilots can't do their certification flights every month thus are rendered not combat-ready."

Another Iraqi military analyst framed the alleged situation as especially concerning, given that the F-16s are "essentially their strongest weapon against ISIS," which still frequently carries out attacks across its collapsed "caliphate" spawning Iraq and Syria.

"We used to fly 16 sorties [a takeoff mission] a day with two jets standby for combat. But now only two-[to-]four sorties a day if we even get airborne. This is due to the lack of proper maintenance and spare parts for the airplanes," a second pilot continued. "So much wasted money. The planes are poorly maintained; it went from 18 to 20 airplanes fully combat-capable to only seven now."

The insider also underscored that while the controversial Iranian-supported militias -- known as the Popular Mobilization Forces (PMFs) and adverse to the U.S and its allies -- have not made use of the F-16s, the fear remains that with little American footprint on the ground, "there would be little to stop them" going forward.

Similar concerns over the F-16s were raised earlier this month by the Iraqi Oil Report, which stressed that the apparent "grounded jets serve as a prime example of expensive U.S. military assistance that has failed to create a meaningful Iraqi military capacity."

Part of the roughly $300 million per year purchase agreement, according to the Iraqi Oil Report analysis, was that Lockheed engineers would "maintain the fleet of fighter jets." The agreement also stipulated that mission equipment and a support package [would be] provided by Lockheed and other companies."

"The F-16 jets continue to fly for training and combat missions even after the withdrawal of the American companies," the ministry said in a statement posted on Facebook last month, muddying the extent to which Lockheed is indeed working with Iraq on the ground, but highlighting that the "Iraqi expertise that has the proven ability to maintain these modern jets, having completed technical workshops at different levels."

A spokesperson for the Iraqi air force additionally told Fox News last week that its top commander had just returned from a visit to Balad Airbase, insisting that there were 19 F-16s, "all of them in good condition" and now reliant on Iraqi technicians and experience, but it was hopeful that Lockheed employees would "return to Iraq very soon."

Moreover, a recent Rudaw article reported that Maj. Gen. Tahsin Khafaji, spokesperson of the Iraqi Joint Operations Command, told Iraqi state media that all the jets are "in good condition," insisting that "Iraqi F-16 fighter jets will continue to target the ISIS remnants, as the jets are all in good condition. Iraqi technicians are constantly working on maintaining the F-16 jets to continue their work targeting ISIS terrorists."

But the denial of problems, according to several Iraqis on the ground, is an immense source of frustration and concern for those tasked with being in the line of fire.

"Since the contractors left Balad, some officials are concerned that the weapons, technology, and components associated with the F-16s could be vulnerable," Foreign Policy wrote, citing a former Iraqi F-16 pilot who also lamented that the Iraqi soldiers on base were not being given adequate food, rest and were operating on "a rotating schedule, with one week on base and one week off so they can seek employment elsewhere, causing potential operations gaps."

Reports have also pointed to Balad Air Force as a prominent point of corruption in the Iraqi military apparatus, ranging from schemes to steal fuel to smuggle on the black market, to Sallyport Security personnel on base becoming embroiled in alcohol smuggling and human trafficking endeavors -- all of which contribute to the calamity and hinder the readiness of pilots in the hot zone.

"Maintenance has long been an Achilles heel for the Iraqi security services, and they have been almost entirely dependent on the United States to keep their planes flying," John Hannah, a national security adviser for former Vice President Dick Cheney and a senior counselor at the Foundation for Defense of Democracies (FDD), told Fox News.

"The F-16s have been based at the Balad airfield, which has been regularly targeted with rockets and mortars by pro-Iranian militias. My view is that the F-16 program could be in serious trouble if the Iraqi government is unable or unwilling to fulfill its most basic international obligation to protect U.S. diplomats, troops, and contractors that they've invited into their country."