KUALA LUMPUR, Nov 28 — Islamic State (IS) militants from South-east Asian countries who fought in Syria may be able to travel home to the region using stolen identities and passports, a former Malaysian Jemaah Islamiyah (JI) leader has warned.

Nasir Abas, a deradicalised leader of the regional extremist group, told South China Morning Post (SCMP) that he had once used a real passport after faking his identity to travel to the southern Philippines and set up a paramilitary training camp.

"I got a genuine Indonesian passport from immigration by using a fake Indonesian ID,” he was quoted telling the Hong Kong daily.

Home Minister Tan Sri Muhyiddin Yassin acknowledged yesterday the possibility of Malaysian and other South-east Asian IS fighters returning home to set up a new terror base following the collapse of its main network in Syria with the death of its leader Abu Bakr al-Baghdadi last month.

Nasir indicated that the availability of regional passports will be much sought after by such radicals to facilitate their movement.

He disclosed that there are three types of passports available for sale: forgeries manufactured at home, those obtained from immigration authorities by way of fake identities, and real passports stolen from their original owners.

"There are scalpers who sell stolen passports. They will sell passports with photos which are similar to the facial features of the buyer. This is not easy, but these scalpers have many passports for a buyer to choose from,” Nasir told SCMP.

The Malaysian now based in Jakarta was arrested on terrorism offences in 2003 and released in 2004, and has spent most of his time assisting the Indonesian government with its deradicalisation efforts.

JI is most notorious for orchestrating the Bali bombing on October 12, 2002, which killed 202 people from over 20 countries, mostly holidaying tourists. However, Nasir was not involved in that incident.

Muhyiddin said Malaysian authorities have increased vigilance following al-Baghdadi's death, as the threat from returning terrorist fighters from abroad, online radicalisation, and lone-wolf attacks is set to grow.

US Department of State Counterterrorism coordinator Nathan Sales has also warned the region that extremist tactics that were widely used in Syria, such as suicide bombings, will likely be adopted by local IS affiliates even if their comrades from abroad don’t return home in masses as predicted.

Indonesia has seen one such suicide bombing at its Medan police headquarters earlier this month.