U.S. Troops Left Syria. What Became of the ISIS Mission?

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The United States completely withdrew its forces from Syria in April 2026 after more than a decade in the country. It handed its last base to the government that replaced the Assad family’s rule, which fell in December 2024. American troops are no longer based there, but the U.S. military still carries out its mission against the Islamic State, or ISIS, from elsewhere in the region.

A U.S. airstrike killed an ISIS leader in Syria in June, U.S. Central Command reported. On September 30, 2026, Central Command announced the end of the Operation Inherent Resolve mission in Iraq while saying the Syria counter-ISIS command remained operational and headquartered in Jordan.

The ceasefire between the Syrian government and the Syrian Democratic Forces, or SDF, began a change in who handles security in northeastern Syria. With the former U.S. partner force being absorbed into government institutions, the continuing mission faces the problem of containing ISIS and keeping its detainees secure through new partners.

Are U.S. troops still in Syria?

No: all U.S. forces left Syria in April 2026, when the Northern Landing Zone, the last open base there, was transferred to the Syrian government, according to the Lead Inspector General’s oversight report to Congress for April through June 2026. The Congressional Research Service calls it an “accelerated departure” that came after the Syrian government reasserted control over northeastern areas secured by a U.S.-supported force, and amid U.S. operations against Iran. Operation Epic Fury began on February 28, 2026, with U.S. and partner strikes on Iranian command facilities, air defenses, missile and drone launch sites, and military airfields, according to Central Command. The forces assigned to the counter-ISIS mission now operate from Jordan, Kuwait, Qatar and the United Arab Emirates, it says.

In December 2024, the Pentagon reported about 2,000 U.S. troops in Syria, clarifying that the 900 previously cited were core personnel supplemented by temporary rotational forces.

U.S. forces had already left At Tanf Garrison, often abbreviated ATG, a base in southern Syria, a day before it was transferred to Syrian government forces on February 12, 2026.

A reported airstrike does not, by itself, show that a force remained based in Syria after the withdrawal.

Why the mission began and how it continues

The United States began airstrikes in Syria in September 2014 to stop ISIS from using Syria as a base for operations in neighboring Iraq. It deployed military forces to Syria in 2015 to fight ISIS and train local partners. The stated purpose was fighting ISIS, not keeping the peace among Syria’s warring groups.

A separate United Nations mission, the United Nations Disengagement Observer Force, supervises the Israeli-Syrian disengagement agreement and maintains their ceasefire in the Golan. Those U.N. peacekeepers are not part of the American counter-ISIS command.

The U.S. campaign against ISIS is called Operation Inherent Resolve, and its command, Combined Joint Task Force-Operation Inherent Resolve, is the military arm of the Global Coalition to Defeat ISIS, a coalition of dozens of countries. The command advises, assists and enables partner forces fighting ISIS. The mission continued after the withdrawal: U.S. Central Command reported that U.S. forces killed an ISIS leader in an airstrike in Syria in June.

The U.S. military also coordinated with Syrian ministries and intelligence services on mine clearance, training, protecting military personnel and counter-ISIS operations through a coordination center in Jordan. The mission is now run from outside Syria, in cooperation with the Syrian government.

Partners and the risk of an ISIS return

The largely Kurdish Syrian Democratic Forces, or SDF, were the principal U.S. partner force in Syria from 2015 to 2026. Turkey opposed Kurdish autonomy and clashed with the main Kurdish group in the SDF over its links to the now-dissolved Kurdistan Workers’ Party, which the United States designates a foreign terrorist organization.

Congressional Research Service reports that ISIS and other extremist groups no longer control territory but have attacked minorities and Syrian and U.S. personnel. In the inspector general’s April-June report, the Defense Intelligence Agency said ISIS attacks in Syria had declined after the U.S. departure, but the group continued targeting Syrian government forces. A decline reported after the withdrawal does not establish that the withdrawal caused it.

In January 2026, when the Syrian government took over northeastern Syria and reached a ceasefire with the SDF, the SDF retreated from about a dozen detention facilities and displacement camps it had been guarding with U.S. support, according to that report. As a result, the report said, about 200 ISIS-affiliated detainees escaped from the Shaddadi detention facility, and as many as 20,000 displaced people left the al-Hol camp. Most escaped Shaddadi detainees were recaptured, while al-Hol closed in February 2026 and most former residents’ whereabouts remained unknown at the end of the reporting quarter. A displaced-person camp is not the same thing as a prison, and its residents should not all be described as fighters.

The commander of the coalition task force said the coalition was responsible for keeping ISIS detainees secure, regardless of which local force or government ran the facilities. Before the departure, U.S. forces transferred more than 5,700 ISIS prisoners from SDF-secured prisons to Iraq. At a February 2026 coalition meeting in Riyadh, participants called on countries to take responsibility for their nationals in Iraq and Syria and bring them home.

What the ceasefire changed

The Assad family’s rule collapsed in December 2024, leaving Syria in a political transition. The Syrian government and the SDF agreed to an initial ceasefire on January 19, 2026 and a permanent agreement on January 29, 2026, beginning the process of integrating the SDF into the government. The ceasefire was between the Syrian government and the SDF; it did not declare the ISIS threat over. What changed is who handles security in northeastern Syria: the government rather than the SDF, with U.S. cooperation against ISIS now running through the government.

Participants at the February 9, 2026 Global Coalition to Defeat ISIS meeting in Riyadh welcomed the permanent ceasefire and arrangements for civil and military integration in northeast Syria, alongside the Syrian government’s stated intention to lead national counter-ISIS efforts. State Department officials said most provisions of the integration agreement were completed or on track by the end of the April-June reporting quarter. The Syrian state news agency SANA reported that Mazloum Abdi announced the SDF’s dissolution as an independent military force on August 25, 2026.

Authority, oversight and the withdrawal debate

Congressional Research Service says U.S. forces operated in Syria from 2014 through 2025 under the 2001 and 2002 Authorizations for Use of Military Force, or AUMFs. Congress repealed the 2002 authorization in the fiscal year 2026 defense authorization law.

The 2001 AUMF authorizes necessary and appropriate force against the nations, organizations or people the president determines planned, carried out or aided the September 11 attacks, or harbored those who did.

In its report for calendar year 2025 on the legal and policy basis for its use of military force, the Trump administration said U.S. forces continued operations against ISIS and al-Qaida in Iraq and Syria under the 2001 AUMF after repeal of the 2002 authorization. The executive branch’s reasoning, described by CRS, treats ISIS as the successor to al-Qaida in Iraq and says its split with al-Qaida did not remove the existing authority to fight it.

Whether to keep troops in Syria was argued in Congress for years before the 2026 withdrawal. When the Trump administration announced in October 2019 that it would withdraw U.S. forces from northern Syria, then-Senator Bob Menendez argued that the decision sacrificed long-term U.S. security while ISIS remained a threat. He warned that Kurdish forces concentrating on self-defense could stop guarding detention sites, creating opportunities for ISIS jailbreaks and recruitment.

Senator Rand Paul later argued for withdrawal, saying the Syria deployment exposed American troops to Iranian-backed militia attacks and risked drawing the United States into another regional war without a congressional debate or vote. His office said Congress had never authorized the use of military force in Syria. Without a declaration of war or congressional authorization, the War Powers Resolution requires a report within 48 hours when U.S. forces enter hostilities or circumstances clearly indicating imminent hostilities. President Obama notified Congress in September 2014 about airstrikes and other actions in Iraq and Syria, citing the 2001 and 2002 authorizations, according to CRS. In December 2023, Paul sought a vote on Senate Joint Resolution 51, which his office called a War Powers resolution and which would have directed withdrawal from hostilities in and affecting Syria within 30 days of enactment. The Senate rejected the motion to bring that resolution out of committee on December 7, 2023, by 13 votes in favor and 84 against.

These were competing judgments about risk: danger to deployed Americans on one side, and danger from weakened partners and detention security on the other.

After the Syrian government and the SDF reached their agreement, Senator Jeanne Shaheen emphasized faithful implementation of it, along with inclusive governance and human rights protections, as part of supporting a stable Syria.

Checking a claim about a soldier or commander

The Federal Trade Commission warns that romance scammers steal photos of military personnel and claim they need money for leave, food or medical treatment during deployment. Its warning says servicemembers do not have to pay to receive packages, food, medical treatment or leave. Treat a request for money from an online love interest as a sign of a scam; a troop count will not settle it.

A claim to be a general stationed in Syria on a peacekeeping mission does not match what official statements describe. The September Central Command statement identifies Admiral Brad Cooper as the regional command’s commander and describes the counter-ISIS command as headquartered in Jordan. A real commander’s name does not prove that someone contacting a reader online is who he or she claims to be.

To evaluate a military claim, check both the date and what the official statement actually describes: a base, a temporary operation or a regional command.