Armed men in uniform, identified by Syrian Democratic forces as U.S. Special Operations forces, ride in the back of a pickup truck in the village of Fatisah in the northern Syrian province of Raqqa on May 25. (Delil Souleiman/Agence France-Presse via Getty Images)

As Syrian fighters push toward the Islamic State’s de-facto capital of Raqqa in northern Syria, Defense Secretary Ashton B. Carter announced Saturday that additional U.S. Special Operations forces will head into the country to help the fledgling offensive.

The additional 200 troops will bolster the 300 or so already in the country, although the number is likely to fluctuate as forces move between Syria and neighboring Iraq. Carter, speaking at a conference in Bahrain, said the forces would include trainers, advisers and explosives specialists.

Other western countries, such as France, also have Special Operations units in the country.

“The increase is tied to the growing number of local forces now willing to participate in this fight, and our efforts to enable them,” a senior defense official, speaking on the condition of anonymity to discuss troop deployments, said in an email before Carter’s remarks.

It is unclear which particular U.S. Special Operations forces are operating in Syria, however the bulk of the U.S. troops in Syria are probably Army Special Forces from Fifth Special Forces Group along with a mixture of Air Force forward air controllers and other Special Operations units. Fifth Group’s primary area of responsibility is the Middle East and North Africa, and it has helped train Syrian fighters in the past. The unit was the first conventional military force to enter Afghanistan after the 9/11 attacks.

Last month, Navy Senior Chief Petty Officer Scott Dayton, an explosive ordnance disposal technician, was killed by a roadside bomb northwest of Raqqa. A tribute to Dayton posted on Facebook identified him as being part of Fifth Group in Syria. His attachment to the unit was confirmed by a U.S. military official familiar with the matter.

A recent article in the Washington Times also pointed to some members of Fifth Group that are growing increasingly frustrated toward their higher-ups for their propensity to micromanage from afar. In an email to the Times, Fifth Group’s commander, Col. Kevin C. Leahy addressed the complaint, saying his troops were right to say their mission is “top heavy” with support personnel.

“There is a sizable amount of people required to provide intel, fires, logistics and vetting of rebels/groups, liaison with host nation partners, U.S. country teams, etc.,” Leahy said in the email. “The teams really are the tip of an inverse triangle of support/[headquarters] needed to enable the mission.”

[Obama outlines plans to expand U.S. Special Operations forces in Syria]

In May, after images on social media of U.S. Special Operations forces in Syria wearing Kurdish patches surfaced, the Pentagon made the troops remove them to avoid angering Turkey.

Special Forces, or Green Berets, specialize in training and advising local forces, a mission known as Foreign Internal Defense, or FID. Images sporadically posted online from local media and individuals on the ground often show what appear to be American forces driving in suburbans and pickup trucks alongside their Syrian counterparts, easily identifiable by their equipment and camouflage patterns.

These troops are “training, advising and assisting,” according to the Pentagon, a line that is often emphasized to reiterate that Americans are not on the front lines fighting the Islamic State and are instead guiding local troops. This approach often runs contrary to how U.S. forces have advised in the past, such as in Iraq, Afghanistan and Vietnam, where U.S. troops would operate directly alongside those who they had been tasked to advise.

Despite the Pentagon’s insistence, footage routinely appears of U.S. troops on or near the front guiding airstrikes. In some cases, it is clear that U.S. Special Operation forces are using specific antitank weapons to take out approaching explosive-laden suicide vehicles.

The newest tranche of Special Operations forces headed to Syria represents the third time since October 2015 that the Pentagon has committed more troops there. The initial deployment was billed as a small group of about 50 that would look for local forces that could potentially fight the Islamic State. The second deployment, announced in April, was for 250 troops that would partner with the forces identified and initially assisted by the first detachment. Now, with approximately 500 of the elite forces in Syria, it means U.S. forces will be able to better manage the local forces they are embedded with, meaning troop movements probably will go smoother, and targeting for airstrikes could occur in more places than before.

The local forces fighting alongside the Americans and other western troops are an amalgamation of Kurdish and Arab fighters known as the Syrian Democratic Forces, or SDF. From its inception in late 2015, the SDF has primarily comprised Kurdish People’s Protection Units, or YPG. The SDF’s predominantly Kurdish composition has been worrying for neighboring Turkey, who sees the YPG as being directly aligned with the Kurdistan Workers’ Party, or PKK — which is recognized by both the United States and Turkey as a terrorist group.

Recruiting and training Arab fighters into the SDF has been one of the top priorities for U.S. forces, as taking back Raqqa from the Islamic State with a mostly Kurdish force could be potentially problematic to the city’s residents and Turkey.

Turkish-backed Syrian fighters, along with Turkish troops, are also fighting in Syria, but they are concentrated to the west around the town of al-Bab.

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