The recent arrests of two radicalised Singaporeans highlight the prevailing threat of extremist ideologies being disseminated online, experts said yesterday, noting that one of them went a step further to travel abroad and meet an extremist cleric face to face.

Kuthubdeen Haja Najumudeen, 36, made three trips to Sri Lanka and met Zahran Hashim, who led April’s Easter bombings at churches and hotels which killed over 250 people, the Ministry of Home Affairs said yesterday.

Associate Professor Kumar Ramakrishna of Nanyang Technological University’s S. Rajaratnam School of International Studies said the “additional step” Haja took to meet personally with an extremist preacher abroad shows how a significant degree of radicalisation can happen, facilitated by social media. “With social media so easily accessible, it is now far easier for extremist ideologies of any stripe to be readily disseminated across national borders,” he added.