M Arifil Azim Putra Norja'I, 19, who was planning to join ISIS abroad, has been kept in custody in Singapore since April on terrorism charges, according to the country's Ministry of Home Affairs (MHA). Arifil is the first known self-radicalized Singapore national who intended to carry out terror attacks in Singapore if he was unable to join the terrorist organization, MHA said, according to Channel News Asia.

Another 17-year old youth has been arrested under the Internal Security Act (ISA), which allows the government to hold suspects in detention for up to two years without trial. The teenager will be held for further investigation into the extent of his radicalization, and his family will be informed of the outcome of the investigation, the MHA said, according to Reuters.

The arrest of these two teenagers comes amidst growing concerns around the world about individuals joining the cause of the Islamic State in Iraq and Syria (ISIS). More than 20,000 foreign fighters have joined the jihadists in Syria and Iraq. ISIS radicalization is growing at an unprecedented rate as the terrorist organization makes gains on the battlefield, The Straits Times reports.

Terrorism remains a serious worldwide threat and the detention of the teenagers indicates that the youth in Singapore are vulnerable to radicalization, according to Teo Chee Hean, deputy prime minister and mome affairs minister. "It is not just a problem that is 'over there' in some other countries. It is also a problem that is 'over here', in our region, and in Singapore as well," he said.