THE HAGUE, Sept. 21 (Xinhua) -- Dutch police arrested 37 people after a protest against asylum policy turned violent in The Hague, with rioters clashing with officers and setting police vehicles on fire, authorities said on Sunday.

"More than 1,000 rioters split off from a demonstration on Saturday afternoon and used a great deal of violence against the police, journalists and the surroundings," police said in a statement. "Four officers and several journalists were injured. A total of 37 arrests were made."

The unrest began when the group began throwing stones and glass at officers. Riot police deployed water cannon after approval from the mayor, who later authorised the use of tear gas at the Malieveld park near the Den Haag Central Station.

Police said rioters attacked with poles and fencing material and torched vehicles. ■