Draw Media, Al-Monitor

Gen. Mark Milley's visit to US troops fighting the Islamic State came as Pentagon officials warn Russia's arms transfers to Iran will embolden the IRGC and its proxies in the Middle East.

Top US general Mark Milley made a surprise visit on Saturday to Syria, where fewer than 1,000 American troops continue to support local militia forces combatting the remnants of the Islamic State (IS) group.

Milley, who serves as the Chairman of the Joint Chiefs of Staff and is ending his term in September, met with the commander of the US-led coalition to defeat IS, Army Maj. Gen. Matthew McFarlane, and reviewed security measures from an undisclosed base in Syria’s northeast.

Why it matters: The arrival of Washington’s top general to Syria signals the Biden administration’s seriousness about keeping troops in the country in support of the Kurdish-led Syrian Democratic Forces (SDF).

Nearly four years after the IS defeat on the battlefield, some 10,000 suspected fighters from the group remain in makeshift prisons under SDF control, with not even a hint of international political will to establish war crimes tribunals on the horizon.

Lingering IS networks have staged at least two major attempts to break their ideological kin out of the facilities over the past year. Early last year, a coordinated IS assault on the Ghweran prison in Hasakah left some 300 fighters dead before the SDF and US regained full control of the area.

“We're committed to maintaining our force presence in support of the enduring defeat of ISIS,”  the Pentagon’s top Middle East policy official, Dana Stroul, told reporters last week.

“This is a mission that has the full support of the Secretary of Defense,” Stroul said.

Down but not out: US and SDF forces continue to track down IS financiers and operatives in northeast Syria, conducting 15 operations together in the month of February alone.

Four US troops and a working dog were wounded on Feb. 16 when a suspected senior Islamic State official triggered an explosion during a nighttime raid on his safe-house.

“There are still aspirations for radical fighters out there to continue to spread ISIS,” coalition commander McFarlane told reporters last week.

The Biden administration is committed to “strategic patience,” Stroul said, as the military continues to build SDF and Iraqi security forces’ abilities to eventually contain IS on their own.

Iraq’s Prime Minister Mohammed Shia al-Sudani has said he supports the continued presence of US military advisers in his country to help prevent IS’ return.

But absent any political resolution to Syria’s decade-long civil war, there’s no sign of an endgame for the US military's role alongside the lightly-armed SDF, whose autonomy is not recognized by the Bashar al-Assad regime in Damascus, and is considered by neighboring Turkey to be a terrorist organization.

Regional context: The top general’s visit suggests Pentagon officials remain keenly attuned to the threats posed to US troops in Syria by another adversary: Iran.

Biden administration officials have grown increasingly concerned that the introduction of Russian technical support for Iran’s already sophisticated arsenal of drones and guided missiles in return for Tehran’s backing for the war in Ukraine will only embolden the IRGC and its proxies in the Middle East.

Militias backed by Iran’s Islamic Revolutionary Guard Corps have a heavy presence west of the Euphrates River in Syria’s east, and launched dozens if not hundreds of rockets and armed drones at US positions in both Iraq and Syria over the past few years.

US troops in the region are not typically authorized to strike at forces other than IS and Al-Qaeda unless acting in self-defense.

Russian pilots have also ramped up their harassment to keep pressure on American forces in Syria over the past year-plus, conducting unauthorized flyovers of US bases on a "daily basis," according to the top US Air Force commander in the Middle East.

"Frankly it’s a bit distracting," Lt. Gen. Alex Grynkewich told reporters last month.

Pushback: Milley’s visit comes just over a week after US Congressman Matt Gaetz (R-Fla.) introduced a war powers bill that would force the Biden administration to withdraw US troops from Syria. The bill is unlikely to clear the House, but a previous measure issued in 2021 gained some bipartisan support.