Islamic State has lost a major strategic city after the fall of Fallujah, but the "West will need to sleep with one eye open" with the terror group thirsty for revenge.
That is the dire warning issued by anti-terror expert Warren Reed who warned the war against Islamic State was far from over.
While the Iraqi forces should celebrate a well deserved victory, Mr Reed said defeating Islamic State would be a "one-by-one-by-one" win.
"This won't be a matter of a domino effect where city after city will fall," he said.
"Instead it will be a hard-fought battle, with Isis popping up like a gofer from the ground and morphing into other areas, particularly overseas with homegrown attacks."
Mr Reed, a senior security analyst who was trained by British spy agency MI6 and served 10 years with the Australian Secret Intelligence Service, said the next target to win back would be Mosul, Iraq's second largest city.
However such a taking would not be easy and while Islamic State may be weakened they will not go down without a fight, he warned.
Mr Reed predicted the loss of Palmyra in Syria earlier this year was the beginning of the end for the terror group but predicted the road ahead would be a long one.
Isis was driven from of its most important strongholds and hundreds of its fighters are dead after Syrian government forces, backed by Russian air strikes, took back control of the ancient city of Palmyra in March.
The ancient city, which endured a 10-month reign of terror, was a major loss for Isis as it cut off a vital access route to its major stronghold, Raqqa.
Mr Reed said Fallujah was just as strategic due to its proximity (60km) to Baghdad.
"It may well be the beginning of the end (for Isis) but we don't know how far that end is, it's too far to see," he said.
"Mosul will be won eventually but it will be a building by building thing and just when a victory is claimed Isis will morph into something else."
He also warned Islamic State will be humiliated by such a loss, like Fallujah, and will be keen to retaliate and strike where it can.
While an attack on the west wasn't as easy from Iraq or Syria, Isis had the potential to launch attacks with foreign fighters on home soil.
Victory in Fallujah
Recapturing Fallujah, the first city to fall to the Islamic State group more than two years ago, means that authorities can now set their sights on militant-held Mosul.
A senior Iraqi commander yesterday declared that Fallujah was "fully liberated" from the Islamic State group in a major boost to the country's security and political leadership in its fight against the extremists.
The battle, which began five weeks ago, comes as Prime Minister Haider al-Abadi vowed that the Iraqi flag would next be raised above Mosul.
Al-Abadi, dressed in the black fatigues of the counter-terrorism forces and carrying an Iraqi flag, visited Fallujah's central hospital yesterday and called for residents of the city to celebrate the military advance.
But tens of thousands of people from Fallujah who were forced to flee their homes during the operation are still at overcrowded camps for the displaced with limited shelter in the Anbar desert.
The US-led coalition said it was still conducting air strikes in the area, and aid groups warned it was too early to say when residents could return to their homes in the city, citing the presence of makeshift bombs left behind by the militants.
The Fallujah operation was carried out by Iraq's elite counter-terrorism troops, Iraqi federal police, Anbar provincial police and an umbrella group of government-sanctioned militia fighters - mostly Shiites - who are known as the Popular Mobilisation Forces.
Fallujah, a predominantly Sunni city, was a stronghold of insurgents following the US-led invasion in 2003.
More than 100 American soldiers died and hundreds more were wounded in intense, house-by-house fighting there in 2004. Many residents of the city welcomed the Islamic State group when it overran the city in 2014, complicating the fight by government troops to retake it.
The Isis militants who had held out for more than a week on the northern and western edges of Fallujah largely collapsed under a barrage from coalition warplanes, including a single air strike that killed 47 fighters in the Jolan neighbourhood, said Brig Haider al-Obeidi of Iraq's special forces.
Al-Abadi initially declared victory in Fallujah more than a week ago, after Iraqi forces advanced into the city centre and took control of a government complex.
He pledged that remaining pockets of Isis fighters would be cleared out within hours, but fierce clashes on the city's northern and western edges persisted for days.
Besides Mosul, Isis extremists still control significant areas in northern and western Iraq, Associated Press reported.
The group, which swept across Syria and Iraq in the summer of 2014, declared an Islamic caliphate on that territory. At the height of its power, it was estimated to hold nearly a third of each country.
The campaign for Mosul, which lies some 360km northwest of Baghdad, has been bogged down by logistics problems as Iraq's political leadership jockeys over the planning of the operation.
Those divisions in the military at times stalled the Fallujah offensive.
A similar scenario is expected to play out in the Mosul campaign, because the various groups that make up Iraq's security forces - including Kurdish forces known as the Peshmerga - have all vowed to participate in the complex operation.
More than 3.3 million Iraqis have fled their homes since the IS advance, according to UN figures. More than 40 per cent are from Anbar province, where Fallujah is located.