As fighting in Marawi City enters a fifth week, Philippine security forces are working to regain control, amid a rising death toll.
More than 350 people have been killed in the fighting between government forces and IS-affiliated fighters in the city in Mindanao Province, according to an official count.
Residents forced to flee have said they have seen scores of bodies in the debris of homes destroyed in bombing and cross-fire.
The seizure of Marawi by fighters from the Maute and Abu Sayyaf groups, and the battle to regain control of it has prompted concerns IS - on the backfoot in Iraq and Syria - is trying to set up a stronghold in the Muslim south of the mainly Roman Catholic Philippines that could threaten the whole region.
IS losing ground in Iraq
In 2014 a terror group, then known as ‘ISIS’, broke into global news coverage with a powerful, sweeping attack from Syria into Iraq.
Taking over territory, weaponry, oil wells and major cities, the group proclaimed a hardline Islamist caliphate and shocked the world with gory execution videos of fighters, foreign aid workers and journalists who were caught in their war.
But a wave of attacks by IS supporters in Europe, the United States and across the Middle East in recent weeks has masked significant defeats against the group’s self-proclaimed caliphate.
As the group is squeezed out of Iraq and faces losses in Syria, experts say the IS is increasingly looking internationally to spread its rhetoric, money and influence.
In South East Asia, it appears IS has found fertile ground.
The rise of the Maute and Abu Sayyaf in the Philippines
Greg Feeley, an Associate Professor with the ANU College of Asia and the Pacific, says a key indicator of the shift in strategy occurred last year, when the group appointed Isnilon Hapilon as ‘Emir’ in South East Asia.
The Filipino militant has been leading a violent Islamist rebellion in the southern Philippines for years, now he’s officially a member of IS.
With tunnels, snipers and food supplies, the group has taken over the majority Muslim city of Marawi and has proved adept at urban warfare despite being outnumbered by Filipino troops.
“The government has been not only surprised, but shocked as well given the loss of lives, and also embarrassed that this group has proved to be so potent militarily and so well prepared,” Feeley said
Fighting alongside Abu Sayyaf are fighters recruited by two Muslim brothers Omarkhayam and Abdullah Maute.
The Maute Group emerged as a small group around 2012, from a decades-old Muslim separatist rebellion in Mindanao and now poses a major threat to security in the Philippines.
But the initial success of the group, that recently announced links to IS - and other such linked groups in the Philippines - contrasts with major losses suffered by the group’s self-proclaimed caliphate in the Middle East.
IS is on the brink of defeat in Mosul, the group’s last major stronghold in Iraq, and faces sustained pressure from coalition and government forces in Syria.
IS is now looking to diversify and decentralize, experts say.
Hapilon’s official IS title of bestows a degree of prestige in jihadist circles, Feeley says, and came after groups in South East Asia jostled for official endorsement from IS.
The group has three things IS values – fighting forces, resources and a degree of territorial control.
But the rise of an IS offshoot in the Asia Pacific isn’t immediate cause for concern for threat levels in Australia, Feeley says.
“The development worsens the level of terrorism threat in South East Asia, but the impact is more for South East Asia than Australia,” he said.
Relatively few IS sympathisers in Australia come from an Asian background, Feeley notes.
'IS-inspired' attacks biggest threat to Australia
Of greater current concern to Australian authorities are so called “lone wolf” attacks, once described by a former ASIO chief as a “recurring nightmare” for the security agency.
“As ISIS comes under growing pressure in Syria and Iraq, it’s certainly both rhetorically and operationally been encouraging people to undertake attacks overseas,” Feeley said.
It’s a new emphasis on a strategy some security experts describe as “remote radicalisation” for “inspired attacks”.
Intelligence agencies say they have been frustrated by the increased availability of encrypted communications enabling would-be radicals.
The Brighton siege earlier this month – in which an innocent man was killed and three police were injured – was claimed by IS as an attack, despite no clear evidence of direct coordination.
“It has violence, it has a shock factor, and so ISIS is taking credit for it,” Feeley said.
“Often what IS is doing is encouraging and taking credit for jihadists who undertake attacks around the world.”
The prominent attacks allow IS to project an image of power and reach, ensuring they remain the biggest ‘brand’ in Islamist terror.
Feeley says in the last 12 months the emphasis has shifted from recruitment of foreign fighters to encouraging home-grown attacks.
The group, which began as an Iraqi Al Qaeda offshoot in the chaos following the US invasion, has proved to be agile and adaptable in the past.
After Syria spun into civil war in 2011, the group moved north from Iraq and became a dominant extremist group among the Syrian chaos.
ASIO head Duncan Lewis told Senate Estimates last month that the threat of Islamist terrorism wasn’t going to end with the defeat of IS in Iraq and Syria.
“Well beyond the physical existence of this so-called caliphate, the threat of terrorism and the threat of a terrorist attack against Australians and Australian interests will continue,” he said.
“This is not the end, and it is not the beginning of the end - it is more like the end of the beginning.”
“We do not see this finishing any time soon.”