The U.S. military released video of airstrikes on Islamic State's targets near Mosul Dam. This video shows a U.S. airstrike on an Islamic State Humvee. (CENTCOM via YouTube)

The U.S. military is relying on bases in the Persian Gulf and elsewhere in the Middle East to carry out airstrikes in Iraq but is masking the locations and other details about the units and aircraft involved to avoid embarrassing partners in the region.

The Persian Gulf monarchies have long hosted U.S. forces­ to bolster their own security. But most have shied away from acknowledging the American presence and are even more reluctant with U.S. warplanes attacking targets in Iraq.

The arrangement is especially delicate given long-standing accusations from Washington that wealthy donors in the gulf underwrite terrorist groups, including Islamic militants being targeted by the Pentagon.

Public records and U.S. military statements about the types of U.S. aircraft deployed over Iraq indicate that they are primarily drawn from three major bases in the gulf: al Udeid Air Base in Qatar, Ali al Salem Air Base in Kuwait and al Dhafra Air Base in the United Arab Emirates.

In addition, Predator drones and possibly other U.S. aircraft are flying from Incirlik Air Base in Turkey, a NATO ally.

Targeting Iraq from next door

Those bases are responsible for launching about two-thirds of the airstrikes in Iraq since Aug. 8, as well as a similar proportion of the thousands of surveillance sorties that have been conducted since June, according to U.S. military commanders.

The remainder have been launched from the USS George H.W. Bush, an aircraft carrier in the Persian Gulf, and other ships in the carrier’s strike group, according to Navy commanders.

The Pentagon has become increasingly dependent on the tiny gulf states to host the bulk of its forces­ in the Middle East since it withdrew from Iraq in 2011 and vacated several large bases there.

Mustafa Alani, director of security and defense studies at the Gulf Research Center in Geneva, said that gulf countries generally support U.S. military action against the Islamic State, the jihadist movement that has taken over large parts of Iraq and Syria. But he said gulf rulers are wary of directly linking themselves to U.S. military operations, fearful of a popular backlash should airstrikes result in civilian casualties.

An ambiguity

“These countries try to protect themselves by not knowing and not asking,” Alani said. Washington has its own reasons to cloak the extent of its military presence in the region, he added. “It is an ambiguity that both sides think they have an interest to maintain.”

The most strategically important U.S. base in the region is al Udeid in Qatar, home of the Air Force’s command center for all air operations in the Middle East and Afghanistan.

The U.S. military released video of targeted airstrikes in northern Iraq. (YouTube: CENTCOM)

An outgrowth of the war in Afghanistan and the 2003 U.S.-led invasion of Iraq, al Udeid is home to about 9,000 U.S. troops and contractors. Its principal unit is the 379th Air Expeditionary Wing, which has more than 90 combat aircraft and support planes.

Even though the base’s existence is an open secret, for years the U.S. military would refrain from uttering its name, saying only that aircraft and personnel there were stationed somewhere in “Southwest Asia.”

That changed, briefly, in December when Defense Secretary Chuck Hagel visited Qatar to sign a 10-year lease extension for the base and publicly acknowledged the presence of U.S. troops. Base officials began issuing statements and news releases mentioning al Udeid.

But since June, when President Obama ordered troops to return to Iraq in small numbers and the skies over the country became thick with U.S. warplanes, military officials have imposed a blackout on information about where those forces­ are coming from.

“Due to host nation sensitivities and operational security, we are not detailing locations of specific bases­ of origin, aircraft or ordnance types,” said Maj. Curtis J. Kellogg, a spokesman for Central Command, which oversees military operations in the Middle East.

Another base that the Pentagon will only identify as being located in Southwest Asia is Ali al Salem Air Base in Kuwait. Nicknamed “the Rock” by U.S. ­forces, it is the closest drone base to Iraq. Predator drones from the Air Force’s 46th Expeditionary Reconnaissance Squadron have to fly only about 40 miles to the border.

Occasionally, military commanders provide hard clues about where U.S. warplanes are flying from. On Aug. 11, Lt. Gen. William C. Mayville Jr., director of operations for the Pentagon’s Joint Staff, told reporters that among the planes carrying out airstrikes were F-15E Strike Eagles and F-16 Fighting Falcons. Squadrons of both fighter jets are routinely deployed to al Udeid.

On Aug. 17, Central Command announced that U.S. bomber aircraft had joined the air campaign. Although it did not give details, officials acknowledged that the statement referred to B-1 bombers, which are also based at al Udeid.

Leverage over U.S. policy

While the stationing of American troops in the Persian Gulf and Turkey has given the Obama administration flexibility, it has also given governments in the region political leverage over U.S. policy.

For instance, the administration has effectively conditioned its military intervention in Iraq on the removal of Prime Minister Nouri al-Maliki, a Shiite leader who resigned this month under pressure. His resignation this month made the U.S. airstrike campaign against the Islamic State more politically palatable for the Sunni rulers of the gulf states and Turkey, who didn’t want Washington to take any action that might help keep Maliki in power.

“From a gulf perspective, there are good interventions and bad interventions,” said Shadi Hamid, a Middle East scholar with the Brookings Institution in Washington. “Maliki was anathema to them and seen as distinctly sectarian.”

At the same time, Hamid said, leaders in the gulf are unlikely to acknowledge their military cooperation with Washington even if they favor the mission. “There will continue to be strong suspicion of anything the U.S. does in terms of intentions and motive,” he said. “It also would be admitting a kind of dependence on the U.S. that would not sit well with the public.”

The suspicion can be mutual. Many officials in Washington and Europe have accused Qatar, Kuwait and the United Arab Emirates of turning a blind eye to fundraising in their countries by clerics and others who support the Islamic State, al-Qaeda and other extremist groups.

Last week, a German government minister, Gerd Mueller, accused Qatar of financing Islamic State militants and helping to arm them. Although the Qatari Foreign Ministry denied the charge and the German government apologized, some in Washington have questioned whether the Qataris have accumulated outsize influence because of their military cooperation.

“They play a good game with us,” former vice president Richard B. Cheney said in June on “The Charlie Rose Show” on PBS. “And the reason is supposedly because we have that big base up there, in al Udeid. . . . So it’s leverage for the Qataris to, in effect, get away with kind of the activity they do with respect to supporting the more radical elements of the jihadi movement.”

Similarly, in Kuwait, even as Ali al Salem Air Base has taken on added importance for U.S. military operations, other branches of the U.S. government have expressed increasing concern about local support for extremist groups. On Aug. 6, the Treasury Department blacklisted three Kuwaitis for allegedly financing the Islamic State and Jabhat al-Nusra, an al-Qaeda affiliate in Syria.