MANILA, June 22 (Xinhua) -- The Philippines and Indonesia are closing ranks in combating the Islamic State (IS)-inspired terrorism in the region, Philippine President Rodrigo Duterte's spokesman said on Thursday.

Speaking at a press conference at the Malacanang presidential palace, Ernesto Abella said that Duterte and Indonesian President Joko Widodo spoke on the phone Wednesday night to discuss the threat posed by local militants allied with IS to the region.

Both Southeast Asian leaders "reaffirmed the need to set up cooperation to address threats posed by terrorism and violent extremism," Abella said.

He said both leaders stressed the importance of the trilateral meeting (among) Indonesia, Malaysia and the Philippines to be held in Manila on Thursday.

During the two leaders' phone conversation, Abella said that Widodo "reaffirmed Indonesia's commitment to support the Philippines in countering terrorism, including restoring peace and stability in the southern Philippines."

He said Duterte welcomed Widodo's "expression of commitment" and emphasized the Philippine government's "full resolvement to work closely together with Indonesia and like-minded states to address these issues."

The foreign ministers of the Philippines, Indonesia and Malaysia are meeting in Manila Thursday to craft common strategies to prevent IS militants from gaining foothold in the region.

Philippine Foreign Secretary Alan Peter Cayetano said last week that "top security personnel" from the three Southeast Asian countries will also join the trilateral meeting on counter-terrorism and fighting extremism.

Cayetano said each country will share perspectives and insights, and discuss strategy and ways on how to strengthen cooperation to counter efforts by IS to establish a caliphate in the region.

"We will be talking about enhanced cooperation, how (the three Southeast Asian countries) can deal with (the terrorist scourge) and how ASEAN can play a more major role in preventing the spillover from Iraq and Syria," Cayetano said.

The Philippines continues to battle terrorism and extremism in the southern Philippines. Duterte has earlier said that militants from Indonesia, Malaysia and even the Middle East are aiding the local militants in the southern Philippines.

An almost month-long firefight is ongoing in southern Philippine Marawi City between the Philippines troops and militants that have expressed allegiance to the IS.

Clashes started when militants overran Marawi city on May 23. At least 369 people have been killed since the firefight broke out, including 67 soldiers and policemen.

Abella said there is "willful and intentional arson activities of the rebels in various areas of the city," adding that the continued use of snipers and IEDs (improvised explosive devices) and RPGs (rocket propelled grenade) from remaining vantage points still remain a challenge.

On Wednesday, another militant group attacked a town in the southern Philippine North Cotabato province where the militants held hostage 31 civilians. All civilians were eventually freed as the militants escaped late Wednesday night.

Duterte warned late Tuesday of more bombings in Mindanao region in the comings days.