ISIS has made a comeback in Syria as U.S. forces draw down, according to an alarming quarterly report from the Pentagon Inspector General released Tuesday.
In the period from April 1 to June 30, the Islamic State terror group continued a successful transition "from a territory-holding force to an insurgency in Syria" while building up its insurgent capabilities in Iraq, the report said.
The withdrawal of U.S. troops limits the support they can give to Syrian Democratic Forces (SDF) east of the Euphrates as the SDF combats new threats from ISIS.
"The reduction of U.S. forces in Syria decreased the support available for Syrian partner forces at a time when they need more training and equipping to respond to the ISIS resurgence," the IG report found.
The report also warned that the SDF could look for "alternate partnerships and resources" as U.S. influence wanes -- possibly from Russia or the Damascus regime.
SDF leaders have previously spoken of turning to the Russians or the regime of Syrian President Bashar al-Assad if they are abandoned by the U.S.
Efforts by the SDF to seek other partnerships would be "detrimental to the United States' mission in Iraq and Syria," according to Combined Joint Task Force-Operation Inherent Resolve, cited in the report.
Among other "serious concerns," is the ISIS resurgence in Iraq, the report stated. Officials with CJTF-OIR, the command overseeing the fight against ISIS, said that "despite improving capabilities of the Iraqi Security Forces, ISIS is rebuilding in remote areas that are hard for these forces to secure."
The report repeatedly referred to the withdrawal of U.S. forces from Syria, but did not give an estimate on how many remain.
When President Donald Trump in December announced his intention to withdraw U.S. forces from Syria, the generally accepted estimate on the U.S. troop strength in Syria was about 2,000, mostly special operations forces.
For security reasons, the Pentagon has declined to discuss a withdrawal timetable or state the number of troops in Syria for security reasons, but local reports have put the number at about 1,000, and the Washington Post used the same figure this week in a report.
Despite Trump's initial call for a complete withdrawal of U.S. troops from Syria, the White House announced that a residual force of about 200 would remain, and would be split between northeast Syria and the al-Tanf garrison near the Jordanian border.
The IG report citing an ISIS resurgence appears to contrast with Trump's frequent claims during campaign rallies that ISIS has been "decimated," or "defeated," or that there is "very little of ISIS left."
The task of remaining U.S. forces in Syria could be further complicated by renewed threats from Turkey to invade SDF-controlled areas in Syria. The threat is that the Turkish military would enter east of the Euphrates River to set up a 20-mile deep safe zone along the border.
Turkey maintains that the mostly-Kurdish YPG (People's Protection Units), the main fighting force within the SDF, is a terrorist organization, a charge that former Defense Secretary Jim Mattis consistently denied.
In Tokyo on his first overseas trip as Pentagon chief, new Defense Secretary Mark Esper said that any Turkish operation into northeastern Syria would be "unacceptable," according to the Associated Press.
SDF leaders have warned in statements to local and Western news outlets that any diversion of forces to meet threats from Turkey would limit their ability to guard camps where thousands of displaced persons and captured ISIS fighters and their families are being held.
The IG report noted CJTF-OIR's estimate "that some 45,000 ISIS supporters and family members reside at the al Hol internally displaced persons camp in Hasakah province" in northeast Syria.
"CJTF-OIR reported that the 'minimal security' provided at al Hol had created the conditions for the uncontested spread of ISIS's ideology within the camp," the report said.
-- Richard Sisk can be reached at richard.sisk@military.com.
