Riot police advanced on Hong Kong democracy  protesters in the early hours of Monday, firing volleys of tear gas after launching a baton-charge in the worst unrest there since China took back control of the former British colony two decades ago.

Some protesters erected barricades to block security forces amid chaotic scenes still unfolding just hours before one of the world’s major financial centers was due to open for business. Many roads leading to the Central business district remained sealed off as thousands defied police calls to retreat.

Earlier, police baton-charged a crowd blocking a key road in the government district in defiance of official warnings that the demonstrations were illegal.

Several scuffles broke out between police in helmets, gas masks and riot gear, with demonstrators angered by the firing of tear gas, last used in Hong Kong in 2005.

“If today I don’t stand up, I will hate myself in future,” said taxi driver Edward Yeung, 55, as he swore at police on the frontline. “Even if I get a criminal record it will be a glorious one.”

White clouds of gas wafting between some of the world’s most valuable office towers and shopping malls underscored the struggle that China’s Communist Party faces in stamping its will on Hong Kong’s more than 7 million people.

China took back control of Hong Kong from Britain in 1997.

Eight years earlier, Beijing’s bloody crackdown on pro-democracy students in Tiananmen Square in 1989 had sent shockwaves through Hong Kong as people saw how far China’s rulers would go to maintain their grip on power.

Thousands of protesters were still milling around the main Hong Kong government building, ignoring messages from student and pro-democracy leaders to retreat for fear that the police might fire rubber bullets.

Australia and Italy issued travel warnings for Hong Kong, urging their citizens to avoid protest sites. Some financial firms in the business district advised staff to work from home or from another location.

The U.S. State Department said in a statement on Sunday that Washington supported Hong Kong’s well-established traditions and fundamental freedoms, such as peaceful assembly and expression.

Sri Lanka Telecom, the country's premier telecommunications provider, announced today in a stock market disclosure that its subsidiary in Hong Kong, SLT Hong Kong Limited was liquidated.

The liquidation took effect from 18 May 2014.

SLT Hong Kong Limited, established in Dec 2006, was a fully owned subsidiary of Sri Lanka Telecom PLC.

Hong Kong can lay claim to the world’s most expensive store, after a 12 square metre shop unit in the city’s exclusive Russell Street sold for a staggering $US23 million ($24.9 million), or just over $2 million per square metre.

Sebastian Skiff, property consultancy CBRE’s Asia executive director, believes that the sale has set a new record, outstripping New York’s Fifth Avenue. “I think it’s the most expensive store, per square foot, the world today,” Mr Skiff said

The current tenant sells small electronic goods.

In an interview with Bloomberg, Mr Skiff said that the store is currently on the market for rent at $HK400,000 ($55,900) per month. It’s contributed to establishing Russell Street in Hong Kong’s Causeway Bay as the world’s most expensive street.

Russell Street first topped the ranks in 2012, taking over from New York’s Fifth Avenue, and continues to stay at the top, with high end retailers superseding traditional mainstream chain stores.

“As a brand, its a great place to be,” said Mr Skiff.

Overall, Hong Kong is considered the most expensive city in the world to rent a shop. In its first quarter report into retail rentals, CBRE Global Research and Consulting put the average annual retail rent in Hong Kong at 33,838 euro per square metre, or $49,800.

This compares to 27,336 euro in New York, and 10,663 euro in London.

Australia’s own retail sector lags in comparison. In Sydney, prime retail space goes for $10,300 a square metre and in Melbourne only $8,800.

Leif Olson, director of retail service at CBRE in Sydney said: “Hong Kong has a huge appetite for retail.”

“There is a also huge demand in all Australian capital cities for [small] strata retail. A lot of people can buy them with their super funds and they can be leased out”.

Mr Olson points to other growing strata retail areas around York Street and George Street in Sydney, as well as areas of Melbourne, although he is still amazed by the prices paid in Hong Kong.

“There is appetite in Australia for small retail, but not to that kind of level.”