A 51-year-old Singaporean who was on his way to Syria to join militant group Islamic State in Iraq and Syria (ISIS) has been detained under the Internal Security Act (ISA).

Mustafa Sultan Ali is the first Singaporean to be arrested abroad for trying to join ISIS, which has attracted 30,000 foreign fighters to territory it controls in Syria and Iraq, including about 1,000 from South-east Asia.

He also told the Singapore authorities that he was prepared to carry out attacks here, the Ministry of Home Affairs (MHA) said in a statement yesterday.

Mustafa, whose occupation was not disclosed by MHA, left Singapore in late May for a neighbouring country and boarded a flight to Turkey from there. He took that route in the hope of hiding his tracks.

Mustafa planned to cross into Syria from the Turkish border, but was detained by the authorities in Turkey. He was deported to Singapore and arrested last month.

"Investigations showed that Mustafa had been deeply radicalised by the terrorist ideology of ISIS and other radical ideologues he had come across online," the MHA said.

"He had travelled to Turkey and tried to make his way to Syria in order to participate in armed violence by fighting alongside ISIS.

"Mustafa also said that he was prepared to carry out ISIS-directed terrorist attacks against Western establishments in Singapore."

Mustafa was issued with a two-year order of detention under the ISA this month.

He is the second person to be detained for terror-related activity this year. In April, student M. Arifil Azim Putra Norja'i, 19, was detained for having made plans to join ISIS in Syria. He also said if he could not do so, he intended to carry out violent attacks here, including to assassinate the president and prime minister. Last month, a 17-year-old self-radicalised youth who had made plans to join ISIS was placed under a restriction order, which limits his activities.

Yesterday, community leaders greeted the announcement of Mustafa's case with dismay, and said it highlighted the worrying reach of ISIS' radical ideology.

They also felt it was worrying that his radicalisation was not detected until his capture abroad.

Dr Mohamed Ali, vice-chairman of the Religious Rehabilitation Group which counsels terror detainees, said the latest case was a reminder that such ideology does not appeal only to impressionable youths, and that the threat posed by such virulent ideas to the region and Singapore was growing.

Dr Mohamed said the Muslim community had to continue efforts to promote a better understanding of the true teachings of Islam, such as promoting peace and respect for followers of other faiths.

But individuals should also look out for warning signs of radicalisation, he said. "We need to monitor not only young people, but also anyone who has the tendency to become radicalised."

At least two Singaporeans are known to have gone to Syria to join ISIS, and both have taken their families and young children along. They are still believed to be there.

The security authorities in the region are also concerned that their citizens fighting in Syria will pose a major threat when they return home, just as an earlier generation of radicals who fought in Afghanistan in the 1980s and 1990s posed a threat when they returned.

The MHA said the Government takes a very serious view of any form of support for terrorism, including but not limited to the use of violence, and will take firm and decisive action against anyone who engages in such activities.

Those who are aware that someone is involved in them should call 1800-2626-473 or 999, it added.

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