Indonesia investigates reports that most senior Southeast Asian Islamic State commander has been killed in Syria

Indonesia is investigating reports from Islamic State (IS) supporters that the most senior Southeast Asian commander of the militant group was killed by US air strikes in eastern Syria last week, counterterrorism officials said.

Online messages from IS propagandists say Bahrumsyah, an Indonesian national, died after US air strikes hit Hajin, north of the Syrian city of Abu Kamal, last Tuesday.

A spokesman for Indonesia’s foreign ministry, Arrmanatha Nasir, said the embassy in Syria had made enquiries but had yet to confirm Bahrumsyah’s death.

Two senior Indonesian counterterrorism officials, speaking on condition of anonymity, said they were taking the online reports seriously.

“We are in the process of investigating,” said one senior official with Indonesia’s counterterrorism agency.

If the reports were true, it would become a “motivation to carry out reprisal attacks” in Indonesia, the senior official said.

A Pentagon spokesman, Eric Pahon, said US aircraft were bombing the “general area” in eastern Syria on the day Bahrumsyah is believed to have died but was unable to confirm his death.

As well as leading Katibah Nusantara, an armed unit comprising more than 100 Southeast Asians, Bahrumsyah also organised funding for the Islamist rebels who captured part of the southern Philippines city of Marawi in a bloody siege last year, analysts and officials say.

A message purportedly from IS figure Abu Nuh said Bahrumsyah had been attending a meeting of leaders when he was killed. An IS headquarters and a vehicle-borne improvised explosive device factory were destroyed in the attack, the message said.

Another post eulogised the Indonesian, receiving sympathetic comments and crying emojis.

There were reports last year of Bahrumsyah’s death, but analyst Sidney Jones from the Jakarta-based Institute for Policy Analysis of Conflict said the latest had a “much higher degree of credibility”.

“As far as we know, he was the highest ranking Indonesian to fight with IS. The fact that he commanded a fighting unit that was recognised by IS underscores his importance,” Jones said.

His death, if confirmed, would be a blow to pro-IS forces in Southeast Asia, where fears of hardened fighters returning from Syria as the militants’ self-declared caliphate crumbles has authorities on alert.

More than 600 Indonesians, including at least 166 women and children, travelled to Syria to join IS, according to data from Indonesia’s counterterrorism agency.

A further 482 Indonesians were deported by foreign governments trying to join IS.

“I don’t expect a flood of people to come back [to Indonesia], although there will be some people trying,” Jones said.