Isis caliphate defeated: How did it happen and do they still pose a threat?

The Isis caliphate, which once stretched for thousands of miles across Iraq and Syria, has been declared defeated.

The Syrian Democratic Forces, a US-backed group of Kurdish and Arab fighters, announced on Saturday that it had captured the last territory held by the group.

"Syrian Democratic Forces declare total elimination of so-called caliphate and 100 percent territorial defeat of ISIS," said Mustafa Bali, a spokesman for group.

"On this unique day, we commemorate thousands of martyrs whose efforts made the victory possible," he added.

But although the terror group may no longer control territory, many questions about its future remain.