HONG KONG (Reuters) - Hong Kong protesters shot arrows and hurled petrol bombs from a barricaded university on Sunday at police who fired tear gas and water cannon in some of the worst violence in the Chinese-ruled city since anti-government unrest erupted five months ago.

Several protesters took up positions on the rooftops of Hong Kong Polytechnic University, armed with bows and arrows, as unrest spread across the territorys central Kowloon district.

Police said a media liaison officer was treated in hospital after being hit by an arrow in the leg and another officers visor was struck by a metal ball although he was not hurt.