Pentagon leaders are increasingly concerned about a possible Turkish military invasion in northern Syria and have begun planning for how it could impact the U.S. fight against the Islamic State terrorist group, according to two senior administration officials and two defense officials.
The main concern is that any Turkish military movement into Syria would draw the U.S. partner, the Kurdish-led Syrian Democratic Forces (SDF), away from the battle against ISIS, the officials said.
“We strongly oppose any Turkish operation into northern Syria and have made clear our objections to Turkey,” Dana Stroul, deputy assistant secretary of defense for the Middle East, said Wednesday during a discussion at the Middle East Institute, a D.C.-based think tank. “Such an operation puts at risk U.S. forces’ coalition campaign against ISIS and will introduce more violence into Syria.”
She warned that Turkish military operations could cause the SDF to focus on moving north to protect their communities from an air campaign or a ground campaign, leaving a vacuum that could allow ISIS to regroup.
“There’s only so many SDF to go around,” Stroul said.
Defense Secretary Lloyd Austin was briefed about the possible invasion earlier this week. He told staff to prepare a U.S. response to Turkish military action and to provide more information about how it could impact the U.S. mission in Syria, according to the officials.
On May 23, Turkish President Recep Tayyip Erdogan said his military was preparing for an operation in northern Syria with the goal of expanding a 30-kilometer (19 mile) security zone that extends south from the Turkish border. The zone was established after another Turkish military operation in 2019.
The new military campaign could involve tens of thousands of Turkish troops and Syrian fighters, according to Turkish officials, who maintain that an ethnic Kurdish group called the People’s Protection Units, or YPG, is attacking Turkish forces. The YPG have been on the front lines in the fight against ISIS, but Erdogan views the group as a terrorist organization and equivalent to PKK Kurdish separatists, who are blamed for attacks inside Turkey.
The Pentagon is particularly concerned about the makeshift prisons the SDF oversees in northeast Syria, according to the senior administration and defense officials. These detention facilities house more than 10,000 ISIS fighters, according to the Department of Defense. The SDF is also responsible for security at the al-Hol and Azraq camps that house more than 60,000 displaced persons, many of whom are believed to be ISIS sympathizers.
If the SDF moves north to counter a Turkish military invasion, tens of thousands of ISIS fighters and sympathizers could potentially be released, the officials said.
Earlier this year, ISIS attacked the largest detention facility in northeast Syria in Hassakeh, releasing thousands of ISIS fighters. While many were recaptured or killed, others escaped and the SDF suffered numerous casualties in the fight.
Stroul warned that ISIS wants to replicate that attack and release more fighters.
“We have seen ISIS’ commitment to targeting these facilities,” she said. “There is no doubt that the group will try to exploit them again if they perceive less counterterrorism pressure in Syria.”
A representative of the Turkish Embassy said its government regards the SDF as a terror syndicate and branch of the PKK in Syria. They blame the PKK and YPG for carrying out more than 1,800 attacks on Turkey from northern Syria in the past two years. The representative said the groups use drones and tunnels to launch attacks and called it “not sustainable.”
The Turkish government has communicated their security concerns to the U.S. government, the representative said. “We will act at a time and place of our choice to respond to the ongoing terrorist attacks that inflict casualties and damage against civilians Syrians and Turks alike.”
In a statement to NBC News, a senior administration official said a "Turkish incursion anywhere into northern Syria would have devastating humanitarian consequences and pose a serious risk to our counter-ISIS campaign."
The U.S. military currently has about 900 troops in northeastern Syria, many partnered with the SDF, providing air support, intelligence, surveillance and reconnaissance, and training. The U.S. does conduct unilateral missions but most counter-ISIS missions are partnered with the SDF.
Without the SDF partners, the current U.S. troop footprint may not be sufficient to continue the counter-ISIS mission, securing the detention facilities and the camps for displaced persons, and providing force protection for U.S. personnel, according to two defense officials. But the Biden administration is not likely to send more troops to Syria, according to the two senior administration officials and two defense officials.
At the same time, the administration would not likely decrease the U.S. presence there, the officials said, in part to avoid the criticism that Washington is once again abandoning its partners in Syria. Former President Donald Trump briefly pulled U.S. troops out of the country in 2019.
With no change in U.S. presence but a potentially very different operational picture after a Turkish invasion, the counter-ISIS mission would either come to a halt or give the terrorist group an advantage.
“Any new offensive will further undermine stability in the area and put at risk U.S. forces and the coalition’s campaign,” Stroul said Wednesday.
Defense officials warn that ISIS remains a real threat and without pressure from coalition operations in Syria, it could grow and present a threat to the region and beyond.
Officials also fear that a Turkish invasion could push the U.S.-allied SDF to partner with Syrian President Bashar al-Assad in the fight against Turkey.
The U.S. military would not engage in combat against Turkey, a NATO ally, so the SDF would need logistical and other support and could look to their foe, the Assad regime. And if Turkey invades without coordinating with the U.S. and other allies, the risk of an accident and escalation grows, according to the officials, as the U.S. military and allies have troops and air assets in northern Syria.