The current government in Hong Kong criticized the USA act on human rights and democracy in the region.
"The will of the Chinese government and the Chinese people to safeguard national sovereignty, security and interest in development is rock solid", Mr Xi said.
Macau returned to Chinese rule on December 20, 1999, with the same "one country, two systems" formula aimed at ensuring a high degree of autonomy under which Hong Kong is governed.
Among other approaches, he considered that Macao must also be a base for the exchange and coexistence of diverse cultures, and can take advantage of the opportunities provided by the Strip and Road Initiative, and the Greater Bay Area.
In Hong Kong, Xi is facing his biggest political challenge yet after more than six months of pro-democracy protests.
A former member of China's top lawmaking body, Ho won a one-horse race this summer to become chief executive - a position that is chosen by a 400-member committee stacked with Beijing loyalists.
A Hong Kong resident was arrested by mainland police last week while crossing into Macau on a newly built bridge linking it to Hong Kong and the mainland city of Zhuhai.
While protesters in Hong Kong are infuriated by what they see as Beijing encroaching on their freedoms, Macau has seen little dissent.
Wall Street continues to push higher led by Communication Services
The broad-based S&P 500 was up a hair at 3,192.52, while the tech-rich Nasdaq Composite Index advanced 0.1 per cent to 8,823.36. In its policy meeting last week, the Fed stood pat on interest rates, as expected, and kept the bar high for future reductions.
Xi gushed with praise for Macau's outgoing Chief Executive Chi Sai On and his officials, congratulating them for adhering to the "Basic Law" of their Special Administrative Region, which is somewhat different from the Basic Law of Hong Kong. But there are stark differences between the two: Hong Kong is a city of 7.5 million people, while Macau's population is less than a tenth of that.
Thursday marks the 35th anniversary of a treaty between China and Britain on Hong Kong's future, that set the stage for its 1997 handover.
In recent weeks, ahead of this week's 20th anniversary of Macau's return to Chinese control, state media have touted the former Portuguese colony as a shining example of how "one country, two systems" can work.
Security checks were also ramped up in Hong Kong's ferry terminals and on a huge bridge and tunnel system linking the two cities.
China has repeatedly portrayed Hong Kong's huge protests as a foreign-backed revolution created to destabilise the motherland, rejecting any suggestion Hong Kongers have legitimate political grievances.
Hong Kong Airlines averted becoming the first carrier to collapse in the city in more than a decade after the Air Transport Licensing Authority said on Dec 7 that it wouldn't take further action against the firm on condition that it raises and maintains enough cash to satisfy the regulator.
"I want to emphasize here that, after the return of Hong Kong and Macao to the homeland, the affairs of the two special administrative regions are completely the internal affairs of China, which need not be pointed out by any external force", said Xi, quoted by the Xinhua agency.
The skyline and market have changed beyond recognition using glittering casinos raking at every week that which Las Vegas collects in per month.