The "one country, two systems" principle has worked well in Macao, which has developed tremendously in the two decades since it was returned to the motherland, Chinese and US diplomats said Thursday in an event at the Chinese Consulate General in New York.

"Today's Macao fully demonstrates that the concept of 'one country, two systems' provides the best institutional arrangement to ensure Macao's long-term prosperity and stability after its return," said Huang Ping, China's consul general in New York, during the event to mark the 20th anniversary of Macao's return from Portugal to China.

In the past two decades, Macao, as a special administrative region (SAR), has enjoyed democracy, economic growth, rising living standards, social harmony and stability and increasing exchanges with the outside world, Huang said.

According to data from the World Bank, its GDP per capita increased from around $15,000 in 1999 to more than $86,000 in 2018. Last year, the International Monetary Fund ranked it as one of the wealthiest places in the world.

The SAR has participated in over 110 international organizations, more than double that before its return to the mainland.

The region's increasingly close interactions and cooperation with the mainland have "injected strong impetus to its development" said Huang, while stressing that the region has kept its distinct features and strengths.

"It's an attraction of being a vibrant metropolis where East meets West has remained as strong as ever," he noted.

"Contacts between the cultures of East and West really began in Macao," said Nicholas Platt, a former US ambassador, who spoke at the event.

Platt, who first visited the region more than five decades ago, said the development of Macao, most notably its robust gambling industry, has made it three times as profitable as Las Vegas, attracting American casinos to invest and make "most of their profits" there.

"'One country, two systems' is working well in a prosperous and stable environment," he said.

While celebrating the development of Macao, Huang expressed concern over the other SAR of China, Hong Kong, which is experiencing months of unrest that involves violent acts.

"It remains the most current task for Hong Kong to bring violence and chaos to an end and restore order," Huang said.

He called for people in all sectors in the SAR to gain a full understanding of the "one country, two systems" principle and "faithfully implement it".

The two systems "should, and have every reason to stay in harmony and reinforce each other" on the basis of "one country", stressed Huang.

"We need to adhere to the 'one country' principle while respecting the differences of the 'two systems' and uphold the power of the central government while ensuring a high degree of autonomy in the SARs," he said.

He also reiterated the Chinese central government's continuous support of the development of the two SARs through frameworks such as the Belt and Road Initiative, the Guangdong-Hong Kong-Macao Greater Bay Area and renminbi internationalization.

"Meanwhile, it is our wish and our request that all external forces should fully respect China's sovereignty [and] avoid interfering in Hong Kong's affairs," he added.