Is the Battle of Marawi a Sign of Things to Come?

As the battle to retake the tiny city of Marawi continues through its second week, a couple of things have become clear.

There are far more militants in control of the city than initially expected, with Filipino officials raising their estimates from 100 jihadis to about 500. There's a contingent of foreign fighters amongst their ranks—Islamist rebels from Chechnya, Pakistan, and Indonesia. And the southern Philippines, a region long-wracked by violence, may now be a new battleground in the fight against ISIS.

"Islamic State capturing a major city in the Philippines is a very significant blow to the security and stability of this region," Rohan Gunaratna, a security expert at Singapore's S. Rajaratnam School of International Studies, told Reuters. "The Filipinos need to get their act together… They must understand the truth that IS ideology took hold in their country. The local groups have transformed."

Filipino security forces had seized control of 90 percent of the city by last Friday. But they've still failed to capture the man who started the whole mess: Isnilon Totoni Hapilon. The crisis in Marawi kicked off when security forces arrived to arrest Hapilon more than a week ago. But the man, the head of the ISIS-linked Abu Sayyaf, responded by calling in reinforcements from the like-minded Maute group—an act that triggered the city's fall.

The plan was, allegedly, to raise the ISIS flag over the province, setting up an Asian foothold for the Islamic State where the terrorist organization could launch new attacks across the region.

The Philippines is far from the "promised land" of Sham mentioned in the Quran, but the country's restive south has long played a vital role in the region's terrorist networks. It was a place where Indonesian militants could retreat and regroup whenever the heat got too heavy back home. That's why few were surprised when Indonesian jihadis were found fighting alongside those who seized the city. Four Indonesians have already been killed in the battle.

"The relationship between militants in the Philippines and Indonesia started a long time ago," Al Chaidar, a terrorism expert who observed Darul Islam's operations in the Philippines, told VICE Indonesia. "Since the early 1990s, Filipino militants have been helping the jihadists in Indonesia. It got more intense since 2014 after they pledge allegiance to ISIS."

Hapilon cut ties with Al-Qaeda and pledged his allegiance to ISIS in 2013. The terrorist group later released a video naming Hapilon as the leader of all ISIS militants in the Philippines. The affiliation was a change of tactics for Abu Sayyaf, a group that was, by then, more well-known as a for-profit kidnapping militia than an Islamist force. But the affiliation, and the directive to seize actual territory for a home base, was enough to pull Hapilon out of the jungle.

Basilan, a small island province, was deemed too small a prize. Hapilon would have to think bigger, according to experts.

"One of the leaders in Basilan, Isnilon Hapilon, moved to Central Mindanao allegedly on the behest of ISIS people in the Middle East to find out if Central Mindanao is more conducive to the establishment of their wilayat," Philippine Defense Secretary Delfin Lorenzana said at a press conference.

Now, as ISIS seemingly helps facilitate greater coordination between regional jihadist groups, experts and government officials have raised the alarm of a new terrorist threat. Indonesian armed forces have already been deployed to North Sulawesi to guard against the potential arrival of any militants fleeing the conflict. The distance between the two countries is only five hours, according to some reports.

"The public might think that the army doesn't care about the current situation, but, that is wrong," TNI spokesman Brig. Gen. Alfret Denny Tuejeh told local media.

And the potential threat of having an ISIS-held province right next door was enough a threat to raise concerns among the highest levels of the Indonesian government.

"As their base [in Syria] was destroyed, they converged and spread combatants to countries of origin to build a new base," Wiranto, Indonesia's top defense minister, told local media. "We will invite New Zealand and Brunei to focus on eradicating terrorists in South Philippines."