On 9 December, the Iraqi Prime Minister Haider al-Abadi declared victory over the Islamic State (also known as ISIS and ISIL), after three years of intense fighting. “Our forces fully control the Iraqi-Syrian border, and thus we can announce the end of the war against Daesh,” said Mr. Abadi.

Two days later was Vladimir Putin to declare victory against both ISIS and Western-backed rebels. “In just over two years, Russia’s armed forces and the Syrian Army have defeated the most battle-hardened group of international terrorists”, said Putin during his visit to Russia’s Hmeymim air base in Syria.

In October a U.S.-backed Syrian force declared victory over ISIS in Raqqa, former capital of the Islamist group, declaring the city free of any extremist presence.

ISIS territory reached its height in 2014, when the group controlled several major cities in Iraq, 9 provinces in Syria and between 100,000 km and 110,000 km of territory in total. By 2017, ISIS has lost control in Iraq and of its major strongholds, and now the Islamist group occupies only a strip of land in Syria, while Islamist fighters try to resist in Libya, Yemen, Algeria, Nigeria, Philippines, North Caucasus, Gaza and in the Sinai province.

ISIS has proved to be incapable to maintain a degree of operational capability in its territory and with the defeat of Raqqa and other major cities, the militants have no longer a stable home to stay. The victory over the self-declared caliphate, however, leaves many open questions on ISIS militants and on hundreds foreign fighters and sympathisers, who abandoned the Islamic State months before it started to crumble.

Around 40,000 people travelled from around the world to take up arms for the ISIS group as it occupied territory in Syria, and it’s unclear how many survived the battles and how many are still fighting. Analysts and experts around the world are trying to estimate how many have survived, but the numbers are uncertain.

“The issue is: how many have died? How many are still there and willing to fight? How many have gone elsewhere to fight?” said Seth Jones, director of the International Security and Defense Policy Center at the Rand Corporation.

Escape routers are still open and during the last battles many Islamist fighters were able to blend in with civilian refugees or bribe their way to sneak into Turkey.

Jean-Yves Le Drian, France’s Minister of Europe and Foreign Affairs, said that about 500 are still in the Iraq-Syria theatre, while France officials affirmed that 250 already returned to France.

Many fighter have no other choice but to still fight for the caliphate in Iraq and Syria, while other militants may join other extremist groups and/or relocate in other war zones. The only thing sure is that those militants have gained battle experience, have nothing to lose and it’s unknown where, when and how they will attack.

Russia and Iraq may have declared victory over Islamic State, but ISIS ideology and franchises are still alive and, as and write on Foreign Affair, there’s a possibility that ISIS could rise again.