BEIJING -- A 140-strong Chinese riot squad left Beijing on Monday for an eight-month United Nations peace-keeping mission in Liberia.

It is the second group of Chinese riot police to head for the western African country since October.

According to the Chinese ministry of public security, all members of the squad went through three months' intensive training on international laws, arms use and language skills before their departure.

Since 2000, China has dispatched more than 2,100 peace-keeping policemen to at least eight regions, including Timore-Leste, Bosnia and Herzegovina, Kosovo, Liberia, Afghanistan, Sudan, Haiti, and South Sudan.