The Hang Seng index lost 2.2%, outpacing falls across Asia, continuing a downward path since Monday.

It comes amid more clashes between protesters and police, and the partial closure of the transport network.

Unrest has gripped the Asian financial hub for nearly five months, knocking the economy and business confidence.

This week has seen a marked escalation in violence with intense street battles, violent clashes at universities and flashmob lunchtime protests in the financial heart of Hong Kong.

"The situation in Hong Kong has taken a decidedly dark turn this week with the violence and economic disruption seemingly gathering pace," Oanda analyst Jeff Halley said.

He said worries about intervention by Beijing have "ratcheted materially higher" keeping Asian markets "cautious at best".

The protests have dealt a blow to the local economy and Hong Kong recently tipped into recession. Tourism and retail businesses have been among those hardest hit as travellers stay away.

"Social unrest, coupled with uncertainty from the US-China trade tensions, have dampened overall business sentiment in Hong Kong," IHS Markit analyst Maojun Ye said.

At the Chinese University of Hong Kong police fired tear gas and rubber bullets as protesters started fires and threw petrol bombs.

Fresh lunchtime protests in the financial district saw crowds gather to chant slogans. Some black-clad protesters also vandalised a branch of the mainland Bank of Communications.

Pro-democracy protests began in June

Why are there protests in Hong Kong?

Hong Kong is part of China, but as a former British colony it has some autonomy and people have more rights.

The protests started in June against plans to allow extradition to the mainland - which many feared would erode the city's freedoms.

The bill was withdrawn in September but demonstrations continued and now call for full democracy and an inquiry into police behaviour.

Clashes between police and activists have become increasingly violent and in October the city banned all face masks.