As the Islamic State in Iraq and Syria (ISIS) loses ground in Iraq and Syria, thousands of foreign fighters may flock back to South-east Asia, bringing with them the radical ideology of the terror group, said Defence Minister Ng Eng Hen yesterday.
He called on religious and community groups to "fight alongside" security forces as "warriors on the ideological front", to prevent people from being radicalised.
"We fully recognise that the war against extremism cannot be won solely through physical might alone... What is crucially needed, and perhaps even more important, is the ideological battle to win hearts and minds through true Islam," he said at the International Conference on Religion and Peace, jointly organised by Jamiyah Singapore and the Islamic Educational, Scientific and Cultural Organisation.
More than 1,000 Malaysians and Indonesians and several Singaporeans are said to have travelled to the Middle East to fight for ISIS. But these foreign fighters may return home as US-led military forces close in on the Iraqi city of Mosul, the terror group's last remaining urban stronghold.
Dr Ng said these fighters may try to entrench the training cells of terror groups in South-east Asia, adding that such cells already exist in Sulawesi in southern Philippines.
To thwart their use of the sea routes to smuggle weapons and people, he said Indonesia, Malaysia and the Philippines have started air and maritime patrols in the Sulu Sea.
He added that Asean defence ministers are "deadly serious" in their counter-terrorism efforts, and have pledged to share intelligence.
But alongside these efforts, community and religious groups are needed to help counter ISIS propaganda that has already "blighted" some young lives, said Dr Ng.
These groups also play a key role in building trust between the different communities, to prevent the spread of suspicion and discord in the aftermath of a terror attack, he said.
"We have to succeed all the time. The terrorist cells only need to succeed once. So we have to prepare Singaporeans for the aftermath of such an attack," he added.