ISIS Last Stronghold Falls - But Leadership Still Unaccounted for as Fighting Continues

US-backed forces in Syria have declared victory over the militant group known as the Islamic State (ISIS) after a key territorial defeat in the group's last holdout in Baghouz.

The more than 10-week long battle to retake the village marked an end to ISIS' self-proclaimed caliphate, said a spokesman for the Syrian Democratic Forces on Saturday.

"Syrian Democratic Forces declare total elimination of so-called caliphate and %100 territorial defeat of ISIS. On this unique day, we commemorate thousands of martyrs whose efforts made the victory possible. #SDFDefeatedISIS" spokesman Mustafa Balisaid in a tweet on Saturday.

SDF's confirmation of the victory comes after President Donald Trump suggested a territorial defeat of the group was imminent, as well as the White House's Friday declaration of victory over ISIS.

"ISIS uses the internet better than almost anyone, but for all of those susceptible to ISIS propaganda, they are now being beaten badly at every level....There is nothing to admire about them, they will always try to show a glimmer of vicious hope, but they are losers and barely breathing. Think about that before you destroy your lives and the lives of your family!" Trump tweeted on Friday.

But although ISIS' final foothold in Syria has been retaken, in a final crushing blow to the militant group that once held a slice of territory the size of Britain, an SDF spokesperson suggested the group's threat was far from over.

"This is a big moment not just for us but for all of the world," SDF spokesperson Kino Gabriel told The New York Times. "But we cannot say that ISIS is finished. It is true that they are finished on the ground as a standing army. But the ISIS threat remains around the globe."

Many key members of ISIS leadership remain anaccounted for, including its founding ideologue and leader, Abu-Bakr el Baghdadi

The warning from the SDF comes on the heels of a similar message from Joseph Votel, the top commander of US forced in the Middle East, who said in February that the fight against ISIS was not over.

"(The caliphate) still has leaders, still has fighters, it still has facilitators, it still has resources, so our continued military pressure is necessary to continue to go after that network," CNN reported Votel saying.

Indeed, following Trump's December announcement that the US would withdraw troops from Syria, a February report from the Pentagon suggested that ISIS would be capable of regrouping in the country within 12 months.