While the helicopters may not arrive in time to help with the current fighting, the missiles are expected to be used by the Iraqi military in the battle to uproot Islamic fighters from Ramadi and Fallujah, cities that were the focus of major U.S. military operations during the height of the war in Iraq. When the U.S. begins sending the first batch of Apache helicopters and additional Hellfire missiles this year, more than 200 private defense-company personnel will be on hand.

They won't be alone.

Across Iraq, military specialists are helping the Iraqi military maintain its growing number of surveillance drones, attack helicopters and powerful missiles. Thousands more support the U.S. government as security guards, analysts, drivers and cooks.

The strategic deployment of defense contractors in Iraq underscores the shifting security landscape as the U.S. downsizes its military presence around the world. With fewer than 200 American military personnel in Iraq, continued U.S. military support there relies increasingly on the presence of contractors.

The role for the military contractors, which has dwindled along with the U.S. presence in Iraq, could become more important in the coming months as the Iraqi government seeks billions more in international military support to combat a growing threat from Islamist militants.

Employees of Bell Helicopter, a unit of Textron Inc., TXT -1.37% are training Iraqi forces to fly and repair light attack helicopters stationed at a military base in the so-called Sunni Triangle northwest of Baghdad, where the Iraqi military is battling resurgent Islamist fighters..

Two dozen Lockheed employees are helping the Iraqi military keep their C-130 transport planes in the air. The company is also sending nearly 500 Hellfire missiles, which are being increasingly used in the fight against al Qaeda militants.

And more than a dozen employees with Beechcraft Corp. and General Atomics maintain a fleet of "Peace Dragon" surveillance airplanes used to track insurgent activity around the country.

The U.S. spent more than $200 billion on contractors in Iraq and Afghanistan over the past decade as its reliance on private support grew, according to congressional estimates. In all, more than 5,000 contractors now work in Iraq as intelligence analysts, security guards, military trainers, translators and cooks.

"You have a situation where the government has become dependent on contractors," said Allison Stanger, a political-science professor at Middlebury College. "It's a real quantum shift."

Most U.S. contractors working in Iraq are unlikely to get involved in direct military operations. Along with U.S. legal restrictions on civilians engaging in combat, foreign military sales contracts often include provisions preventing contractors from being involved in direct combat, said Anthony Cordesman, a defense expert at the Center for Strategic and International Studies.

"Almost all of them will be protected from being asked to, or participating in, combat," Mr. Cordesman said. "You can't require anyone to have any kind of direct combat role."

Still, contractors serve in dangerous areas. In Afghanistan, more civilian contractors were being killed than U.S. soldiers by 2012, according to an analysis by Steven Schooner, a professor at George Washington University Law School. Now, he said, the traditional U.S. military role has been supplanted by civilians who are training and equipping the Iraqi military.

"The military task has, in fact, been outsourced in Iraq," he said.

The U.S. troop withdrawal from Iraq in 2011 brought the war to an official end. But the U.S. still retains a large presence at the embassy in Baghdad, which is still one of the biggest American diplomatic facilities in the world.

Over the past few years, the U.S. has been scaling back its presence in Iraq, and even the contractor force has dwindled.

As of January 2013, the U.S. had more than 12,500 contractors in Iraq, according to State Department and Pentagon figures. The U.S. has significantly reduced that number over the past year.

Of the roughly 5,000 contractors supporting the American diplomatic mission in Iraq, the State Department said, more than a third of them are U.S. citizens. They work for companies like Triple Canopy Inc., which provides security guards for U.S. diplomats, and L-3 Communications Holdings Inc., LLL -0.90% which helps the State Department vet Iraqis seeking jobs with the U.S. Many serve as cooks, translators and janitors.

Those numbers don't account for scores of military contractors working in Iraq as part of U.S.-approved foreign military sales that provide the Iraqi government with helicopters, missiles and other critical support.

U.S. lawmakers, led by Sen. Robert Menendez (D., N.J.), had blocked the Apache helicopter sale because of concerns that the Iraqi government would use them to crack down on minority groups.

Those concerns have now been allayed and the U.S. is stepping up its help as the Iraqi government tries to quash Sunni militants in Anbar province.

“You have a situation where the government has become dependent on contractors,” Allison Stanger, a political-science professor at Middlebury College, told WSJ. “It's a real quantum shift.”

“The military task has, in fact, been outsourced in Iraq,” confirmed analyst Steven Schooner, a professor at George Washington University Law School.

Washington’s relationship with Baghdad has undergone a major transformation. Officially, the US has just several hundred troops in Iraq and the US Defense Department does not contract private security companies to operate in Iraq.

Yet the major shift in US-Iraq relations now is that Washington is no longer allocating budget money on operations in Iraq. It is Baghdad that spends money on American weaponry, vehicles and equipment, while American defense companies are earning money in Iraq by placing military contractors there.

Private defense companies, such as Triple Canopy and Dyncorp International, have multibillion contracts in Iraq for years to come.

Washington is actively assisting the Iraqi government in fighting terrorism, supplying Baghdad with drones and is considering training some of the country’s elite military forces in neighboring Jordan.

An assault operation against the Islamic State of Iraq and the Levant (ISIS), a faction of Al-Qaeda currently occupying Fallujah, is promising to be a serious undertaking implying the use of the utmost in firepower, so Baghdad is buying $6 billion worth of military equipment from the US, including 24 Apache attack helicopters and nearly 500 Hellfire missiles.

A group of top US lawmakers attempted to block the Apache deal, expressing concerns that providing Iraq with helicopters and other arms to help battle Al-Qaeda, would also mean that Iraqi Prime Minister Nouri al-Maliki might use them against his rivals. But the deal has nevertheless been finalized and the first batch of helicopters is expected in Iraq soon, along with the Hellfire missiles. This also means that 200 more contractors will come to Iraq to ensure the helicopters operate properly.

In the meantime violence in Iraq is at a record high. Al-Qaeda militants are advancing in the country’s south and are staging regular terror acts. It seems the Iraqi government has little choice but to come down on the insurgency with deadly force.

History repeats itself

It is probably no exaggeration to say that the war in Iraq is as far from being over as it was in 2003, with two major differences though. First: in the absence of Saddam Hussein his troops have been replaced with Al-Qaeda mujahedeen. Second: the US regular army has been supplanted by thousands of contractors, the Wall Street Journal reports.

The rest remains the same: English-speaking mercenaries are expected to choreograph the storming of Iraqi cities defended by Arab-speaking fighters of Al-Qaeda, exactly as it was back in 2004 during the Battle of Fallujah. Today Fallujah, occupied by Al-Qaeda, remains the primary target for the Iraqi government forces to assault backed by mercenaries.

US troops entered Iraq in 2003 and officially withdrew from the country in 2011. At the peak of war there were 157,800 American military personnel in Iraq.

Pentagon spokesman, Navy Commander Bill Speaks, reported that there are only 250 American troops in Iraq. These servicemen are either advisers assigned to the Office of Security Cooperation overseeing the US military interaction with Iraqi national forces, or Marine Corps security guards securing US diplomatic facilities.

After the withdrawal of the US troops from Iraq, the duty of protecting US interests in the country was relegated to thousands of contractors from the US Defense Ministry and other security agencies.

According to the US State Department and Pentagon, it is estimated there were over 12,500 contractors in Iraq, working for the US government as of January 2013. By October, according to a quarterly report, their number had decreased to 6,624 specialists. Less than a quarter of them (1,626) were American citizens, the rest were Iraqis (2,191), with 2,807 civilian experts from foreign countries.

Bill Speaks said that the last major US Defense Department contract in Iraq ended on December 15 and now there are zero contractors in Iraq hired by the US Defense Department.

Where did all those contractors go? They are still in Iraq, maintains the Foreign Policy magazine.

The FP asked Triple Canopy, a huge private defense company and sanctuary for the US Special Forces veterans, for details and learnt that “Recently all US government agencies have reduced their reliance on contractors due to budget cuts and have de-scoped contracts across the board, including in Iraq,” the company said a statement.

“Contractors will continue to remain engaged in Iraq in the near future. However, the majority of these personnel will likely be working on commercial extractive and construction projects,” the company said.

Contractors from America's biggest defense companies are providing maintenance for the equipment and vehicles previously bought by the Iraqi government from the US, such as helicopters, C-130 transport aircrafts, surveillance planes, drones, communication equipment and more.

Over the years of the wars in Iraq and Afghanistan there have been multiple cases of contracting fraud.

The US Congress’ Independent Commission on Wartime Contracting determined that at least $31 billion in US funding had been wasted due to “poor oversight, fraud, waste, and abuse,” said FP’s former US Representative, Christopher Shays, who used co-chair the Commission.

The US has allegedly spent over $200 billion on contractors in both Afghanistan and Iraq over the last decade. Now that the US administration has transferred these expenditures to the Iraqi government, the American military industrial complex and private security companies are ready to make a fortune in Iraq.