China's paramilitary People's Armed Police marched and practiced crowd control tactics at a sports complex in Shenzhen, the city that links Hong Kong to  mainland China. The move is interpreted as a threat against pro-democracy protesters in the semi-autonomous territory.<br />'' <br />'' Chinese state media said that the Shenzhen exercises were planned earlier and were not directly related to the unrest in Hong Kong. Weeks of protests in Hong Kong have been marked by increasing violence and a shut down of the Hong Kong airport earlier this week. <br />