An Indonesian jihadist suspected of working for the Islamic State (Isis) is building a sophisticated militant network in his hometown Solo in Central Java, counter-terrorism officials said. Bahrun Naim, who is believed to be operating from Raqqa — the IS (Daesh) stronghold in Syria — was recently linked to the foiled Marina Bay rocket attack in Singapore.

Indonesian authorities fear that Naim's recruitment of militants raises the risk of major attacks in the country. It is suspected that many of his new recruits belong to Team Hisbah — a local militant outfit founded by Sigit Qurdowi, whose death about five years ago led to the fragmentation of the group.

Indonesia had managed to contain the spread of Islamist militancy following a crackdown on al-Qaeda franchise Jemaah Islamiyah in 2000. However, IS is reportedly reviving the fragmented radical groups in the country, Indonesian authorities told Reuters.

Naim worked as a link between IS and Team Hisbah members in Indonesia when he ran an internet cafe in Solo, the Jakarta-based Institute for Policy Analysis of Conflict (Ipac) told the news agency. However, the suspected IS co-ordinator disappeared in January 2015 following a brief prison term for a 2011 conviction over possession of ammunition. He was believed to have moved to Syria to join the terror group.

His militant connection came to light following his identification as the mastermind of the January Jakarta attacks. Reuters quoted a senior counter-terrorism official as saying that Naim uses his contacts in Solo to pick vulnerable people who could easily be radicalised. "After online contact is established, he will teach them how to make bombs and give them tactical instructions on how to plan attacks," the official added.

However, his recruits are amateurs and not capable of launching major attacks, believes Mahmud of the IS Supporters Forum. "They cannot get materials like in the Bali bomb," he said referring to the 2002 bomb attacks on night clubs in Kuta Beach in Bali that killed 202 people, mostly foreigners.

The senior counter-terrorism official believes the scenario is changing. "They may look amateurish now. But the pattern in which they seem to be moving and organizing themselves means it's only a matter of time before they can launch a dangerous attack," the official added.

According to data from Indonesia's financial transactions watchdog, nearly $800,000 (£606,577) has so far been transferred since 2014 from foreign countries to Indonesia-based Islamist groups. However, it was not clear how much of it came from Naim, who is now on the country's most-wanted list.

Edi Lukito, leader of an Islamic anti-vice squad called Laskar Umat Islam Surakarta reportedly said he was aware of regular bank payments Naim made to at least one of his young recruits in the city. "This young generation has an extraordinary passion for jihad and they want to carry guns quickly," Lukito said, adding he does not support IS.