“I hereby declare Marawi city liberated from the terrorist influence,” declared Philippine President Rodrigo Duterte shortly after the country’s military killed this week the reputed top brass of Islamic State (IS)-affiliated militants in the country.

Almost five months into the siege of Marawi, security officials this week verified the death of Isnilon Hapilon, the designated ‘emir’ of the IS movement in Southeast Asia, and Omar Maute, the top military commander of the IS-linked Maute Group in the Philippines. Omar’s brother, Abdullah, was killed in September, decapitating the eponymous group’s twin leadership.

The military has killed as many as 800 militants and freed up to 1,700 hostages, while suffering around 162 casualties since the Muslim majority city’s siege began in May. Mahmud bin Ahmad, a Malaysian doctor who has served as a conduit between IS’ command in Raqqa and the Filipino militants, is still at large.

Filipino security officials said on Thursday that there was a “big possibility” that he, too, has been killed in recent fighting.

His capture alive would be crucial to deciphering the complex networks which serve as a bridge between IS’ leadership in the Middle East and its emerging Southeast Asian proxies. Intermittent firefights have continued across the city, with several foreign fighters still holding hostages and refusing to surrender to the authorities.

ATTENTION EDITORS - VISUAL COVERAGE OF SCENES OF DEATH Chief of Staff of the Armed Forces of the Philippines Eduardo Ano shows reporters a picture of killed Abu Sayyaf Isnilon Hapilon and Omar Maute, leader of the Maute-Islamic State group, during a news conference at the military headquarters in Marawi City, Philippines October 16, 2017. REUTERS/Froilan Gallardo TEMPLATE OUT
Philippine armed forces chief of staff Eduardo Ano shows pictures of killed Islamic State emir Isnilon Hapilon and Maute Group leader Omar Maute, October 16, 2017. Photo: Reuters/Froilan Gallardo

The Philippine military, however, has not been triumphalist about the news of the top-level militant deaths. Officials are now cautiously assessing the situation on the ground before giving the green light for the return of hundreds of thousands of displaced Marawi residents.

Nonetheless, the prospect of an IS “wilayah“, or autonomous province, in the Philippines seems for now to have been contained. This, Duterte declared, “marks the beginning of rehabilitation” in the devastated city, many parts of which have been reduced to rubble. At the same time, the months-long siege has transformed the Armed Forces of the Philippines (AFP) into a nimbler force against urban-based insurgents.

For the past decade, Hapilon repeatedly eluded Philippine authorities. In fact, it was the failed raid on Hapilon’s safe house which triggered the siege of Marawi by IS-aligned militants.

A leader of the Abu Sayyaf Group (ASG), an extremist franchise that has been active with high-profile kidnap-for-ransom and recently piracy operations in southern maritime areas, Hapilon had deftly reached out across geographical and ethnic fault-lines to build a larger IS-affiliated movement in the country.

Over the past year, Hapilon managed to establish a large and potent coalition of IS-affiliated groups, with rising support from regional Islamic extremist groups as well as IS’ leadership in Syria. His alliance with the Maute Group, whose stronghold of Butig in Lanao del Sur lies across from Marawi, proved crucial to sustaining the drawn-out siege.

A mannequin dressed in a military uniform with a dummy sniper rifle is displayed in front of a military post at Mapandi town in Marawi city, southern Philippines October 19, 2017. REUTERS/Romeo Ranoco     TPX IMAGES OF THE DAY
A mannequin dressed in a military uniform with a dummy sniper rifle is displayed in front of a military post at Mapandi town in Marawi city, southern Philippines October 19, 2017. Photo: Reuters/Romeo Ranoco

The Maute brothers, Omar and Abdullah, brought in substantial financial and logistical resources, not to mention advanced military and theological training from the Middle East. The death of Hapilon and the Maute brothers would at first blush seem to indicate the elimination of IS’ politico-military leadership in the Philippines.

Intelligence, logistical and training assistance from traditional allies such as the United States and Australia, as well as new strategic partners China and Russia, was crucial to helping the AFP to cope with its first major experience in urban warfare. The Philippine military has decades of experience fighting rebel groups in rural and jungle settings.

The battle against Islamic extremism, however, is far from over. Other IS-affiliated groups such as the Bangsamoro Islamic Freedom Fighters (BIFF), which is active in Mindanao’s Maguindanao region, and the ASG, based in the country’s southernmost remote island region, will almost certainly seek to continue where the Maute Group left off.

The months-long siege on Marawi, which drew praise and admiration from jihadist circles worldwide, notably at a time IS was being routed in Syria and Iraq, has provided valuable lessons as well as inspiration for an ambitious new generation of Muslim extremists in Mindanao, officials say.

That Islamist movement, targeted in the US-led global ‘war on terror’, has proven resilient and adaptive over the years to the battlefield killings of its leaders. A local militant and former ASG deputy, Furuji Indama, is now expected to assume Hapilon’s leadership position.

However, it remains to be seen if he can forge and maintain as potent and audacious an alliance as his ambitious ASG predecessor.

Damaged houses and buildings are seen as the government troops continue their assault against the pro-Islamic State militant group during a clearing operation in Marawi city, southern Philippines, October 18, 2017. REUTERS/Romeo Ranoco
War-damaged houses and buildings in Marawi city, southern Philippines, October 18, 2017. Photo: Reuters/Romeo Ranoco

With the setback to IS’ ambition to establish a wilayah in Mindanao, the next generation of IS-affiliated leaders is expected to switch, at least initially, to more targeted and spectacular terrorist attacks. That would be akin to IS’ tactical shift to high-profile terror attacks in late 2014 after suffering repeated military setbacks in its heartland.

As the Philippine government draws down its full-scale military operation in Marawi, with notable but quiet assistance from American Special Forces and Australian surveillance aircrafts, it is already under pressure to ramp up its intelligence-gathering capacities to prevent terror attacks in major urban centers, including outside of Mindanao.

In early November the Philippines will host global leaders, including US President Donald Trump, for the multilateral East Asia Summit to be held in Manila and Clark. The protection of foreign dignitaries and key commercial hubs is expected to dominate Duterte’s security agenda in coming months.

The bigger long-term challenge, however, will be the efficient reconstruction of Marawi and the reintegration of its 600,000 displaced residents who have endured dire conditions in makeshift refugee camps. The failure to do so, analysts warn, would provide fertile ground for new waves of recruitment to IS’ radical cause.

Duterte’s government will also need to double down on peace negotiations with major rebel outfits such as the Moro Islamic Liberation Front, a ceasefire group which is reportedly intent on preventing radicalization within its own ranks, as well as deploying troops in a way that neutralizes the chance of IS gaining a new stronghold.