Hong Kong democracy protesters defied volleys of tear gas and police baton-charges to stand firm in the center of the global financial hub on Monday, one of the biggest political challenges for Beijing since the Tiananmen Square crackdown 25 years ago.
The unrest, the worst in Hong Kong since China resumed its rule over the former British colony in 1997, sent white clouds of gas wafting among the world's most valuable office towers and shopping malls as the city prepared to open for business.
Televised scenes of the chaos also made a deep impression on viewers outside Hong Kong, especially in Taiwan, which has full democracy but is considered by China as a renegade province which must one day be reunited with the Communist-run mainland.
The protests, led mostly by young tech-savvy students who have grown up with freedoms not enjoyed in mainland China, represent one of the biggest threats confronted by Beijing's Communist Party leadership since it launched a bloody crackdown on pro-democracy student protests in Tiananmen Square in 1989.
"Taiwan people are watching this closely," Taiwanese President Ma Ying-jeou said in an interview with Al Jazeera.
China rules Hong Kong under a "one country, two systems" formula which accords the territory limited democracy. The protesters are demanding Beijing give them full democracy, with the freedom to nominate election candidates, but China recently announced that it would not go that far.
Organizers said as many as 80,000 people thronged the streets over the weekend, after the protests flared on Friday night. No independent estimate of crowd numbers was available.
The Hong Kong Monetary Authority (HKMA), the city's de facto central bank, said it had activated business continuity plans, as had 17 banks affected by the protests.
The HKMA said the city's interbank markets and Currency Board mechanism, which maintains the exchange rate, would function normally on Monday. It said it stood ready to "inject liquidity into the banking system as and when necessary".
Read MoreHong Kong protests explained
Hong Kong witnessed extraordinary scenes at the weekend as thousands of protesters, some armed with nothing more than umbrellas, blocked the main road into the city and police responded with pepper spray, tear gas and baton charges.
Markets more or less took the weekend's unrest in their stride, proof yet again of the pre-eminent place trade has always taken in Hong Kong.
Hong Kong shares fell 2.3 percent.