MANILA, Philippines—The recent abductions of three Westerners and a Filipino woman from a southern Philippine resort are the latest reminder of the long-running security problems that have hounded a region with bountiful resources and promises, but hamstrung by stark poverty and an array of insurgents and outlaws.

READ: Filipina, 3 foreigners abducted on Samal Island

While authorities have not identified the abductors with certainty, there is one usual suspect: the Abu Sayyaf group, a brutal al-Qaida-linked organization that has pulled off mass kidnappings for ransom in the last 15 years in the south and in neighboring Malaysia.

“The primary suspect is ASG,” regional military commander Lt. Gen. Aurelio Baladad told reporters Thursday. He added, however, that there have been no conclusive findings on the kidnappers’ identities.

Under cover of darkness, at least 11 men armed with two rifles and pistols barged into the Holiday Ocean View Samal Resort on southern Samal Island shortly before midnight on Sunday and then headed toward yachts docked at a marina, according to the military and police.

In less than 20 minutes, the kidnappers herded at gunpoint Canadians John Ridsdel and Robert Hall, Norwegian Kjartan Sekkingstad, the resort’s marina manager, and Filipino Teresita Flor, to two motor boats.

An American and his Japanese female companion fought back and were injured, but escaped by jumping off their yacht, said Senior Superintendent Samuel Gadingan, the police chief of Davao del Norte province, where Samal is located, about 1,000 kilometers (600 miles) southeast of the capital, Manila.

READ: Authorities believe Abu Sayyaf behind abduction of Filipina, 3 foreigners

Aside from the Abu Sayyaf, investigators have considered the possible involvement of a small extortion gang of former Muslim and communist guerrillas, who have an active presence in the vast Davao region. The latter, however, have in the past publicly declared their abductions, mostly of government troops, within days of seizing them, according to Gadingan.

It remains uncertain which group is behind the latest abduction, but the conditions that foster such crimes are much clearer: a volatile mix of poverty, weak law enforcement and access to thousands of unlicensed firearms in the south, said Julkipli Wadi, dean of the Institute for Islamic Studies at the state-run University of the Philippines.

It’s very likely too that those deep-seated social ills would not be solved anytime soon and kidnappings will continue, he said.

“These are generational problems that are difficult to be solved by presidents who are restricted to six-year terms and often lack political will,” Wadi said.

Kidnappings for ransom have preceded the Abu Sayyaf. But the group started an alarming trend of large-scale abductions after it emerged in the early 2000 as an offshoot of the decades-long separatist rebellion by minority Muslims in the predominantly Roman Catholic nation’s south.

The Abu Sayyaf abducted 21 people, mostly European tourists, from a Malaysian diving resort in 2000, freeing them later, reportedly in exchange for huge ransoms. The militants took three Americans and 17 Filipinos the following year from the Dos Palmas resort in Palawan province southwest of Manila, then staged a failed kidnapping attempt at a popular resort on Samal Island, near where Sunday’s abductions occurred.

Without any known foreign financial support and after more than a decade of battle setbacks inflicted by US-backed Philippine military offensives, the Abu Sayyaf has survived mostly through kidnappings and extortion. In recent years, they have grown more daring by crossing the sea border to snatch victims in Malaysia’s Sabah state.

The US military’s antiterrorism task force in the southern Philippines was deactivated in February after 13 years, as Washington recently shifted focus to supporting freedom of navigation in the South China Sea. US forces continue to provide intelligence and training to Filipino troops in the south.

The rewards for Abu Sayyaf kidnappers have been relatively huge. Aside from the money, kidnap victims have been used as human shields to pre-empt government offensives. High-profile abductions also have allowed the militants to capture the attention of foreign terrorist networks, a confidential government security assessment report said.

Last year, the militants were estimated to have pocketed more than 277 million pesos ($6 million) in ransom from the kidnappings of 59 people, said the report, a copy of which was obtained by The Associated Press.

“Kidnapping has indeed become a lucrative industry in Mindanao,” the report said, referring to the southern region. It added, without elaborating, that unidentified corrupt politicians and even law enforcers have benefited from the crime.

Buddy Recio, a Filipino travel writer who was abducted by Abu Sayyaf militants with his wife and son at the Palawan resort in 2001, said it pains him to know that the militants have endured and continue to seize innocent people, who have to go through the same harrowing ordeal that they endured.

Recio’s son was freed and he and his wife were wounded in crossfire, prompting the Abu Sayyaf militants to leave them after a week of captivity. If the new kidnap victims could hear him, Recio said he would advise them to stay fit to endure the extremely rough time ahead and to look forward to a brighter ending.

“They should keep on hoping,” Recio said. “They should think that there are governments and friends working to set them free.”