Kurdish-led forces captured the main ISIS hub of Hajin Friday, a milestone in a massive and costly US-backed campaign to drive the jihadists out of eastern Syria.

The Syrian Democratic Forces secured Hajin, the largest settlement in what is the last pocket of territory controlled by ISIS, the Syrian Observatory for Human Rights said.

“After a week of heavy fighting and air strikes, the SDF were able to kick [ISIS] out,” said Rami Abdel Rahman, the head of the UK-based monitoring group.

The operation was completed at dawn, he said, a day after SDF forces fanned out across the large village in the Euphrates Valley.

On Thursday, the last ISIS fighters were confined to a network of tunnels and the edges of Hajin, which lies in the eastern province of Deir Ezzor, about 30 kilometers from the border with Iraq.

The area held by ISIS is sometimes referred to as the “Hajin pocket,” the last rump of a once-sprawling “caliphate” the group proclaimed in 2014 over swathes of Syria and Iraq.

ISIS fighters withdrew to positions east of Hajin Friday and to Sousa and Al-Shaafa, the other two main villages in their shrinking Euphrates Valley enclave.

– with reporting by Agence France-Presse