MARAWI CITY • Dozens of foreign militants have fought side-by-side with Islamic State in Iraq and Syria (ISIS) sympathisers against security forces in the southern Philippines over the past week, evidence that the restive region is fast becoming an Asian hub for the radical group.
A Philippines intelligence source said that of the 400 to 500 fighters who overran Marawi City on the island of Mindanao last Tuesday, as many as 40 had recently come from overseas, including from countries in the Middle East.
"ISIS is shrinking in Iraq and Syria, and decentralising in parts of Asia and the Middle East," said Professor Rohan Gunaratna, a security expert at Singapore's S. Rajaratnam School of International Studies. "One of the areas where it is expanding is South-east Asia and the Philippines is the centre of gravity."
Mindanao has been roiled for decades by bandits, local insurgencies and separatist movements. But officials have long warned that the poverty, lawlessness and porous borders of Mindanao's predominantly Muslim areas mean it could become a base for radicals from South-east Asia and beyond, especially as ISIS fighters are driven out of Iraq and Syria.
Although ISIS and its affiliated groups have claimed several attacks across South-east Asia in the last two years, the battle in Marawi City was the first drawn-out confrontation with security forces.
Last year, South-east Asian militants fighting for ISIS in Syria released a video urging their countrymen to join the cause in the southern Philippines or launch attacks at home rather than travel to Syria.
Jakarta-based terrorism expert Sidney Jones passed Reuters some recent messages from a Telegram group used by ISIS supporters.
In one, a user in Marawi City reported that he could see the army "run like pigs" and "their filthy blood mix with the dead bodies of their comrades".
He asked others in the group to pass information on to the Amaq News Agency, a mouthpiece for ISIS.
Another user replied, using an Arabic word meaning pilgrimage: "Hijrah to the Philippines. Door is opening." The clash in Marawi City began with an army raid to capture Isnilon Hapilon, a leader of Abu Sayyaf, a group notorious for piracy and kidnapping.
Abu Sayyaf and a relatively new group called Maute, both of which have pledged allegiance to ISIS, have fought alongside each other in Marawi City.
The head of the Malaysian police force's counter-terrorism division Ayob Khan Mydin Pitchay named four Malaysians who are known to have travelled to Mindanao to join militant groups.
Among them were Mahmud Ahmad, a Malaysian university lecturer who is poised to take over the ISIS leadership in the southern Philippines if Hapilon is killed, he said.
According to Prof Gunaratna's school's research, eight of 33 militants killed in the first four days of fighting in Marawi City were foreigners, an unusually high number.
Indonesian officials believe 38 Indonesians travelled to the southern Philippines to join ISIS-affiliated groups with 22 joining the fighting in Marawi City, according to an intelligence brief seen by Reuters.
Some may have slipped into Marawi City under the cover of an annual gathering of the Tablighi Jamaat, a Sunni missionary movement, just days before fighting erupted.