Businesses, officials and major media outlets from across the globe have underlined heavy tolls and lessons from the rampant violence in Hong Kong, calling for an end to the rioting in the Asian financial hub at an early date.

Many firms, agencies and individuals closely connected to the special administrative region have felt the great pains and inconvenience caused by the chaos escalating in the past week, including the rioters' moves to universities in the city to carry out their attacks and violence.

A slew of flight changes released in recent days via leading online aviation industry information portal Routesonline.com showed that several Asian airlines such as Thai Airways have curtailed their flights to Hong Kong in the coming weeks, amid lingering security concerns and sluggish passenger demand.

The Philippine Airlines is "adjusting operational frequencies" for the Manila-Hong Kong route in the fourth quarter of this year, as the carrier schedules four daily flights, instead of five, the website reported on Sunday.

The unrest of almost six months "has pushed the Asian financial hub into recession for the first time in a decade", Reuters commented on Monday.

Michael Reynal, who manages more than $2 billion in emerging-market equities at Victory Capital Management in Des Moines, Iowa, of the United States, said, "The protests in Hong Kong have taken a very violent turn, and talking to my colleagues out there, gives me a sense that we are seeing a radicalization of the protest movement which is not widely supported."

"We care about the Hong Kong exchange being stable and open as a trading platform for Chinese securities," Bloomberg quoted Reynal as saying on Monday.

An editorial published by The Guardian newspaper on Tuesday said, "Though many remain peaceful, a radical minority of protesters have responded with unacceptable violence."

"Many in Hong Kong will deplore that decision and were rightly repelled when a man was set on fire last week, apparently by a protester," the editorial said in reference to the attack that led to the local resident's death last week.

Hedley Thomas, national chief correspondent of The Australian newspaper, wrote on Tuesday that Hong Kong's "well-resourced and highly disciplined police force has been cast by the protesters and influential sections of the local and international media as a public enemy".

"The protesters are Hong Kong's enemy right now, but few dare say it," he said. "In this volatile atmosphere, anyone who publicly challenges their (the rioters') cause, who seeks to call out the violence and the damage, is at risk of fierce reprisal."

Singapore's Trade and Industry Minister Chan Chun Sing told local media on Monday that "Hong Kong's continued success as an economic and financial hub is important for the region and the world, including Singapore".

"What has happened in Hong Kong can easily happen to Singapore if we are complacent or not careful," the minister said in a group interview for sharing the lessons Singapore has learned from the chaos in Hong Kong.

The minister warned that, "To insist on maximum individual gains at the expense of the common and collective good cannot be the Singapore way. The pursuit of such narrow interest will instigate fraction."

"Singapore's continued relevance to the world is never a given. We must work hard, distinguish ourselves and stay exceptional amidst global uncertainties," he said.