About 200 low-level Islamic State terrorists escaped Syria's Shaddadi prison on Monday after guards from the Kurdish-led Syrian Democratic Forces left the facility, but Syrian government forces recaptured many of them, a US official said on Tuesday.

The official, speaking to Reuters on condition of anonymity, said about 600 foreign fighters from Islamic State had been transferred from Shaddadi prior to January 19 to other facilities and remain in detention.

Syria's Interior Ministry said on Tuesday that about 120 Islamic State terrorists escaped from Shaddadi prison, after the Kurdish website Rudaw reported that a spokesperson for the Kurdish-led Syrian Democratic Forces, Farhad Shami, said around 1,500 Islamic State (ISIS) terrorists had escaped.

The Syrian ministry said Syrian army units and ministry special forces entered Shaddadi following the breakout. It said security forces had recaptured 81 of the escapees after search and sweep operations in the town and surrounding areas, with efforts continuing to arrest the remaining fugitives.

Earlier, the Syrian army said "a number of" Islamic State terrorists had escaped a prison that had been under SDF control in the eastern city of Shaddadi, accusing the SDF of releasing them.

A Syrian national flag flutters next to the Islamic State's slogan at a roundabout where executions were carried out by ISIS militants in the city of Palmyra, in Homs Governorate, Syria April 1, 2016.
A Syrian national flag flutters next to the Islamic State's slogan at a roundabout where executions were carried out by ISIS militants in the city of Palmyra, in Homs Governorate, Syria April 1, 2016. (credit: REUTERS/OMAR SANADIKI)

After days of fighting with government forces, the SDF agreed on Sunday to withdraw from both Raqqa and Deir al-Zor, two Arab-majority provinces they had controlled for years and the location of Syria's main oil fields.

The Syrian country has detained thousands of alleged ISIS members lately, who are being held in about two dozen camps and prisons run by the US-backed Syrian Democratic Forces.

Syria detains thousands of ISIS members

These facilities were largely created as a result of the defeat of ISIS from 2017-2019 in Syria. When the last major pockets of ISIS control were liberated by the SDF in 2019, thousands of ISIS family members ended up in the hands of the SDF.

After clashes between the SDF and the Syrian government over the past week, an agreement was signed that is supposed to mean the administration of ISIS detainees in eastern Syria will be handed over to the Syrian government.

The detainees in eastern Syria include mostly women, and their children, who had married ISIS members. They also include thousands of foreigners.

Seth J. Frantzman contributed to this report.