Hong Kong police fired water cannon and tear gas and arrested nearly 200 people on Wednesday as protesters took to the streets in defiance of sweeping security legislation introduced by China that critics say is aimed at snuffing out dissent.

Only a handful of protesters remain at ``Poly U,'' which hundreds occupied for several days, fighting pitched battles with police in the surrounding streets. Authorities have cut off the campus and are arresting anyone who comes out, at least 700 since Sunday.

Concerns over Hong Kong's political and economic future are growing as pro-democracy protests drag on and turn increasingly violent.

"Hong Kong doesn't look like how it did before," said one protest organizer.

"They are young people and they are doing the right thing. Why are they being mistreated?"