JAKARTA, Indonesia — Sembara Oktafian was in the engine room of a tugboat chugging toward the Philippines when something didn’t sound right.
There was shouting on deck, and shots. Gunmen had boarded, and their message was clear: Come with us, or we will kill you. They shot one crew member and kidnapped four others.
“They were a terrible-looking group, running around with AK-47s,” Mr. Sembara said. “I thought they were going to kill us all, but they only took my friends.”
The April attack, in the Celebes Sea south of the Philippines, was not isolated, or even out of the ordinary. Southeast Asia now accounts for the majority of seafaring attacks globally, surpassing the Horn of Africa, according to the International Maritime Bureau. And governments in the region are scrambling to combat the problem.
“In Somalia, the attacks have gone down,” said Noel Choong, the head of the maritime bureau’s piracy reporting center in Kuala Lumpur, the capital of Malaysia. “In Nigeria, the numbers are still there, but not as much as in Asia.”
In 2015, there were 178 attacks in Southeast Asia and none in the Gulf of Aden and Red Sea region near Somalia, according to the maritime bureau, after a multinational security crackdown there. The bureau also reported that in the first half of this year, Southeast Asia was the scene of more than one-third of the 98 attacks and attempted attacks globally.
The men who attacked the tugboat, an Indonesian-flagged vessel that had been hauling a coal barge, were later identified as members of Abu Sayyaf, an extremist group based in the southern Philippines that has acted as a hostage-for-ransom gang for more than two decades. It has also pledged its allegiance to the Islamic State.
Abu Sayyaf is responsible for most of the kidnappings at sea in Southeast Asia, but several other criminal gangs also operate in those waters.
Between March and August, Abu Sayyaf kidnapped 25 Indonesian and six Malaysian seamen in attacks along vital trade routes for coal barges in the Sulu Archipelago. The extremist group continues to hold nine Indonesian sailors from the recent attacks.
Alarmed by the spate of kidnappings for ransom, Indonesia, Malaysia and the Philippines agreed in May to conduct coordinated naval security patrols in the Sulu Archipelago, and establish a hotline among themselves. In August, they agreed to allow “hot pursuits” of kidnappers and armed robbers by their maritime security forces into one another’s territory.
“The idea is for the closest patrol boat to take the necessary action,” said Arrmanatha Nasir, an Indonesian foreign ministry spokesman.
The Indonesian Navy thwarted the hijacking of an oil tanker by pirates off the southwest coast of Borneo in May, and arrested nine suspects. But attacks on oil tankers have become less frequent as global fuel prices have dropped, according to a recent report by the Global Initiative Against Transnational Organized Crime.