The police of Hengyang in Hunan Province detained a 35-year-old man on Saturday who allegedly threatened on a Sina Weibo microblog account to stage a massacre at a train station. One day later, the people's procuratorate of Changshu in Jiangsu Province arrested a man on charges of spreading terrorist and extremist content online. He allegedly spread a horror video depicting bloody scenes on WeChat. The case is under investigation.  

As our dependence on the internet increases, so do threats posed by cyber terrorism. At a time when online terrorism has become a grave challenge worldwide, the two cases deserve our attention.

Terrorism doesn't merely refer to organized terror attacks. The threat of violence or the dissemination of articles, images, speeches or videos online that promote terrorism or encourage violence are also forms of terrorism. There must be a zero tolerance policy.

Although the US often points an accusing finger at China's clearing of online terrorist content, Washington itself has adopted a harsh attitude toward those making online terrorist threats. A 22-year-old Texas man was recently released from three years in prison for using fake email accounts, Twitter accounts and internet-based phone accounts to threaten to kill a police officer and her family.

China is a victim of cyber terrorism. Its western region of Xinjiang has been plagued by violent terror attacks in recent years. One of the most important and direct reasons is that the East Turkestan Islamic Movement took advantage of the internet to disseminate propaganda and inspire new followers.

Sixteen terrorists launched an attack in Lukqun, a township in Turpan prefecture of Xinjiang on June 26, 2013, leaving 35 dead. The principal criminal of the gang, Ekrem Usman, confessed that they watched online videos which instigated them to launch jihad.

As the internet brings people closer, a grave reality is that it has also become an increasingly powerful tool for terrorists and made it easier for them to reach more people, share information, coordinate attacks, raise funds and recruit. Not just China but many countries in the world are facing terrorism too rampant, serious and persistent to diminish anytime soon. By no means can we allow the internet to slip into becoming a haven for terrorism.

One effective way is to intensify surveillance, better police what is available online, severely crack down on content that promotes terrorism and strengthen anti-online terrorism legislation. This is what China is doing now.