This undated photo provided by the Armed Forces of the Philippines, young Abu Sayyaf commander Moammar Askali, who used the nom de guerre Abu Rami, is seen at an unknown location in Sulu province, southern Philippines.

The killing of a Muslim extremist leader on a resort island in the central Philippines this week was a clear victory for the military, but it also drove home an unsettling reality: that the militants are venturing farther from their jungle hideouts to spread terror.

Military chief of staff Gen. Eduardo Ano said that troops recovered and identified the remains of Abu Sayyaf group commander Moammar Askali at the scene of the battle in the coastal hinterlands of Bohol island. Five other Abu Sayyaf gunmen, three soldiers and a policeman also were killed in Tuesday’s clashes.

“This is a major blow to the Abu Sayyaf,” Ano told The Associated Press on Wednesday. “If they have further plans to kidnap innocent people somewhere, they will now have to think twice.”

“We are gaining important headway in our fight to degrade the ASG in regard to our timeline,” Ano later told a news conference, referring to a military objective to considerably cripple the extremist group of more than 300 armed fighters within six months.

Former Abu Sayyaf militants identified Askali from a photo troops took of the young militant leader after his death, confirming that the gunmen who quietly cruised into Bohol on three motorboats under cover of darkness late Monday before clashing with troops belonged to the Islamic extremist group. Askali, who used the nom de guerre Abu Rami, had partly served as an Abu Sayyaf spokesman in recent years.

Askali was an emerging hard-line leader of Abu Sayyaf and had pledged allegiance to the ISIS group. Abu Sayyaf was founded in 1989 as an offshoot of a decades-long rebellion by minority Muslims in the south of the predominantly Roman Catholic Philippines. He had received bomb-making training from Malaysian Zulkifli bin Hir, or Marwan, a top Southeast Asian militant leader who was killed in 2015, according to a police profile.

It was Abu Sayyaf’s first known attempt to carry out ransom kidnappings deep in the central Philippine heartland, far from the group’s jungle lairs in the southern provinces of Sulu and Basilan. Ano said the troops were still hunting for at least five Abu Sayyaf gunmen, though fighting had eased Wednesday.

While the bold kidnapping attempt appears to have been foiled, the militants’ success in penetrating the bustling region of beach resorts and other popular attractions could raise concerns among tourists and businessmen.

The US Embassy in Manila had earlier advised Americans to take precautions amid “unsubstantiated yet credible information” of possible kidnappings by terrorists in Bohol and other central areas.

The United States and the Philippines both list Abu Sayyaf as a terrorist organization for bombings, kidnappings for ransom and beheadings.

Bohol island lies about 640 kilometers (397 miles) southeast of Manila and is about an hour by boat from Cebu province, a trade and tourism center that has hosted some of the meetings of the Association of Southeast Asian Nations, the regional bloc the Philippines is leading this year.

Ano said military intelligence operatives had been trying to track the movements of Askali’s group for several days after learning of their planned abductions.

The gunmen traveled on motorboats along a river into a village in Bohol’s Inabanga town where government forces assaulted them, military officials said, adding that troops recovered four rifles, a homemade bomb and a sack load of bomb-making materials from the slain gunmen.

In past years, Abu Sayyaf militants have crossed the sea border with Malaysia on powerful speedboats and kidnapped scores of foreign tourists, reflecting their growing capability and desperation for money. In 2001, they sailed as far as western Palawan province, where they seized 20 people from a resort, including three Americans, one of whom was beheaded and another shot and killed during an army rescue.

Although they rely mainly on ransom kidnappings, Abu Sayyaf has displayed incredible resiliency and has survived through US-backed military offensives under six presidents.

Philippine President Rodrigo Duterte, who took office in June, has ordered troops to destroy the extremists and has threatened to declare martial law in the country’s south if the threat posed by Abu Sayyaf and other extremist groups aligned with the ISIS group gets out of control.

Although weakened by years of battle setbacks, the militants again hogged headlines last year when they separately beheaded two Canadians then decapitated a German hostage earlier this year after ransom deadlines lapsed. Askali was involved in those kidnappings and the captives’ gruesome murders, Ano said.

The militants are still holding at least 29 captives in Sulu’s jungles.

A confidential government threat assessment report obtained by the AP last year said that the militants have started to target slow-moving tugboats crisscrossing the Sulu Sea and the busy sea border between the southern Philippines, Malaysia and Indonesia in their effort to avoid constant military offensives in the southern provinces where they operate and raise desperately needed funds.

In the first half of last year, the militants raised 353 million pesos ($7 million) in payments from ransom kidnappings, according to the report.