Dec. 14 (UPI) — The U.S.-backed Syrian Democratic Forces captured Hajin in eastern Syria Friday, the final stronghold and de facto capital for the Islamic State, officials said.

The SDF forces completely control Hajin following violent firefights that drove out the Islamic fighters. U.S. aircraft launched airstrikes against the terrorists in support of the Kurdish-led SDF.

Officials said militants moved their forces to the outskirts of the city, near the Iraq border, where they are still engaging Syrian Democratic Forces.

In a last ditch-effort, Islamic State forces blended in with the population and set up sleeper cells that hid mines in trees, on roads and in other inconspicuous places.

President Donald Trump said this week he expects the group, also known as ISIS, would be defeated within a month.

“There are very few of them left in that area of the world,” Trump said Tuesday. “Within another 30 days, there won’t be any of them left. Since I took office, we’ve driven ISIS out of nearly all of the territory it once held in Syria and Iraq, devastating the caliphate.”

Trump said he will sign legislation in a few months to assist ethnic and religious minority groups in Syria and Iraq who have been targeted for genocide. The bill would also give U.S. authorities the ability to bring them to justice.

Hajin is in Deir ez-Zor province, where an estimated 225,000 civilians have been displaced.

Thursday, Turkish President Recep Tayyip Erdogan said his forces will launch a military operation to “wipe out” Kurdistan Workers Party and People’s Protection Unit separatists east of the Euphrates River. Both groups targeted by Turkey are backed by the United States.